diff --git a/.gitignore b/.gitignore
index 723ef36..713ed43 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1 +1,3 @@
-.idea
\ No newline at end of file
+.idea
+
+*.db
\ No newline at end of file
diff --git a/app.py b/app.py
index f05f9fd..0ac759f 100644
--- a/app.py
+++ b/app.py
@@ -1,30 +1,56 @@
+import logging
 import os
 import uuid
 from urllib.parse import urlparse, urljoin
 
 import flask
-from flask import Flask, redirect, render_template, request
+from flask import Flask, redirect, render_template, request, g
 from flask_login import LoginManager, login_required, login_user, logout_user, UserMixin, \
     current_user
 from flask_wtf import CSRFProtect
 
-from forms import RegistrationForm, LoginForm
+from db import get_db, get_registration_codes, add_registration_code, \
+    expire_registration_code, delete_registration_code
+from forms import RegistrationForm, LoginForm, RegistrationCodeForm, \
+    ExpireRegistrationCodeForm
 
-app = Flask(__name__)
+csrf = CSRFProtect()
+login_manager = LoginManager()
 
-app.config.update(dict(
-    ADMIN_TOKEN=os.getenv("ADMIN_TOKEN", uuid.uuid4().__str__()),
-    SECRET_KEY=os.getenv("SECRET_KEY", "changeme"),
-    WTF_CSRF_SECRET_KEY=os.getenv("CSRF_SECRET_KEY", "csrf_changeme")
-))
+log = logging.getLogger(__name__)
 
-print("Admin Token: %s" % app.config.get("ADMIN_TOKEN"))
 
-csrf = CSRFProtect(app)
+def init_db(flask_app):
+    with flask_app.app_context():
+        db = get_db()
+        with flask_app.open_resource('schema.sql', mode='r') as f:
+            db.cursor().executescript(f.read())
+            log.info("Initialized DB")
+        db.commit()
 
-login_manager = LoginManager()
-login_manager.init_app(app)
-login_manager.login_view = "admin_login"
+
+def create_app():
+    flask_app = Flask(__name__)
+
+    flask_app.config.update(dict(
+        ADMIN_TOKEN=os.getenv("ADMIN_TOKEN", uuid.uuid4().__str__()),
+        SECRET_KEY=os.getenv("SECRET_KEY", "changeme"),
+        WTF_CSRF_SECRET_KEY=os.getenv("CSRF_SECRET_KEY", "csrf_changeme")
+    ))
+
+    print("Admin Token: %s" % flask_app.config.get("ADMIN_TOKEN"))
+
+    csrf.init_app(flask_app)
+
+    login_manager.init_app(flask_app)
+    login_manager.login_view = "admin_login"
+
+    init_db(flask_app)
+
+    return flask_app
+
+
+app = create_app()
 
 
 class User(UserMixin):
@@ -73,7 +99,36 @@ def registration():
 @app.route('/admin')
 @login_required
 def admin_index():
-    return render_template('admin.html')
+    context = {
+        'add_registration_code_form': RegistrationCodeForm(),
+        'registration_codes': get_registration_codes()
+    }
+    return render_template('admin.html', **context)
+
+
+@app.route('/admin/add_registration_code', methods=['POST'])
+@login_required
+def admin_add_registration_code():
+    form = RegistrationCodeForm()
+    if form.validate_on_submit():
+        expiration_time = form.expiration_time.data
+        max_usages = form.max_usages.data
+        add_registration_code(expiration_time, max_usages)
+        redirect('/admin')
+    return redirect('/admin')
+
+
+@app.route('/admin/expire_registration_code', methods=['POST'])
+@login_required
+def admin_expire_registration_code():
+    form = ExpireRegistrationCodeForm()
+    if form.validate_on_submit():
+        if form.expire.data:
+            expire_registration_code(form.registration_code.data)
+        elif form.delete.data:
+            delete_registration_code(form.registration_code.data)
+        redirect('/admin')
+    return redirect('/admin')
 
 
 @app.route('/admin/login', methods=('GET', 'POST'))
@@ -107,5 +162,12 @@ def admin_logout():
     return redirect('/')
 
 
+@app.teardown_appcontext
+def close_connection(exception):
+    db = getattr(g, '_database', None)
+    if db is not None:
+        db.close()
+
+
 if __name__ == '__main__':
     app.run()
diff --git a/db.py b/db.py
index 5e7d323..317ac88 100644
--- a/db.py
+++ b/db.py
@@ -1,11 +1,30 @@
 import os
 import sqlite3
+import uuid
+from datetime import datetime
+from typing import Optional
 
 from flask import g
 
+from models import RegistrationCode, RegisteredUser
+
 DATABASE = os.getenv("DATA_DIRECTORY", ".") + "/data.db"
 
 
+REGISTRATION_CODE_INSERT_SQL = """INSERT INTO
+registration_codes(code, creationTime, expirationTime, usages, maxUsages)
+VALUES(?, ?, ?, ?, ?)"""
+
+REGISTRATION_CODE_UPDATE_SQL = """UPDATE registration_codes 
+SET expirationTime = ?, usages = ?, maxUsages = ? 
+WHERE code = ?"""
+
+REGISTERED_USER_INSERT_SQL = """INSERT INTO
+registered_users(username, registeredTime)
+VALUES(?, ?)
+"""
+
+
 def get_db():
     db = getattr(g, '_database', None)
     if db is None:
@@ -13,8 +32,91 @@ def get_db():
     return db
 
 
-@app.teardown_appcontext
-def close_connection(exception):
-    db = getattr(g, '_database', None)
-    if db is not None:
-        db.close()
+def _query_db(query, args=(), one=False):
+    cur = get_db().execute(query, args)
+    rv = cur.fetchall()
+    cur.close()
+    return (rv[0] if rv else None) if one else rv
+
+
+def get_registration_codes() -> [RegistrationCode]:
+    registration_codes = []
+    for registration_code in _query_db("SELECT * FROM registration_codes"):
+        registration_codes.append(RegistrationCode.from_db(registration_code))
+    return registration_codes
+
+
+def get_registration_code(code: str) -> Optional[RegistrationCode]:
+    return RegistrationCode.from_db(
+        _query_db("SELECT * FROM registration_codes WHERE code = ?", [code], one=True)
+    )
+
+
+def add_registration_code(
+        expiration_time: datetime = datetime.now(),
+        max_usages: int = 1) -> RegistrationCode:
+    code = RegistrationCode(
+        uuid.uuid4().__str__(), expiration_time=expiration_time, max_usages=max_usages)
+    db = get_db()
+    db.execute(
+        REGISTRATION_CODE_INSERT_SQL,
+        [code.code,
+         code.creation_time,
+         code.expiration_time,
+         code.usages,
+         code.max_usages]
+    )
+    db.commit()
+    return get_registration_code(code.code)
+
+
+def update_registration_code(code: RegistrationCode) -> RegistrationCode:
+    db = get_db()
+    db.execute(REGISTRATION_CODE_UPDATE_SQL,
+               [code.expiration_time, code.usages, code.max_usages, code.code]
+               )
+    db.commit()
+    return get_registration_code(code.code)
+
+
+def expire_registration_code(code: str):
+    db = get_db()
+    db.execute(
+        "UPDATE registration_codes SET expirationTime = ? WHERE code = ?",
+        [datetime.now(), code]
+    )
+    db.commit()
+
+
+def delete_registration_code(code:str):
+    db = get_db()
+    db.execute(
+        "DELETE FROM registration_codes WHERE code = ?",
+        [code]
+    )
+    db.commit()
+
+
+def get_registered_users() -> [RegisteredUser]:
+    registered_users = []
+    for registered_user in _query_db("SELECT * FROM registered_users"):
+        registered_users.append(RegisteredUser.from_db(registered_user))
+    return registered_users
+
+
+def get_registered_user(username: str) -> Optional[RegisteredUser]:
+    return RegisteredUser.from_db(
+        _query_db("SELECT * FROM registered_users WHERE username = ?", username, one=True)
+    )
+
+
+def add_registered_user(code: str, username: str) -> RegisteredUser:
+    registration_code = get_registration_code(code)
+    registration_code.usages += 1
+    update_registration_code(registration_code)
+    db = get_db()
+    db.execute(REGISTERED_USER_INSERT_SQL, [username, datetime.now()])
+    db.commit()
+    return get_registered_user(username)
+
+
diff --git a/forms.py b/forms.py
index 8d3687e..af98352 100644
--- a/forms.py
+++ b/forms.py
@@ -1,14 +1,40 @@
 from flask_wtf import FlaskForm
-from wtforms import StringField, PasswordField
-from wtforms.validators import DataRequired
+from wtforms import StringField, PasswordField, DateField, IntegerField, SubmitField
+from wtforms.validators import DataRequired, Length, EqualTo, InputRequired, \
+    ValidationError, NumberRange, Optional
+import safe
+
+
+def safe_password_validator(form: FlaskForm, field):
+    strength = safe.check(field.data, level=safe.MEDIUM)
+    if not strength.valid:
+        raise ValidationError("Password is not secure enough: %s" % strength.message)
 
 
 class RegistrationForm(FlaskForm):
-    username = StringField('Username', validators=[DataRequired()])
-    password = PasswordField('Password', validators=[DataRequired()])
+    username = StringField('Username', validators=[DataRequired(), Length(min=3, max=30)])
+    password = PasswordField(
+        'Password',
+        validators=[
+            InputRequired(),
+            EqualTo('confirm', message='Passwords must match'),
+            safe_password_validator
+        ])
+    confirm = PasswordField('Repeat Password')
     registration_code = StringField('Registration Code', validators=[DataRequired()])
 
 
 class LoginForm(FlaskForm):
     username = StringField('Username', validators=[DataRequired()])
     token = PasswordField('Token', validators=[DataRequired()])
+
+
+class RegistrationCodeForm(FlaskForm):
+    expiration_time = DateField('Expiration Time', validators=[Optional()])
+    max_usages = IntegerField('Max Usages', validators=[NumberRange(min=1)])
+
+
+class ExpireRegistrationCodeForm(FlaskForm):
+    registration_code = StringField('Registration Code')
+    expire = SubmitField(label='Expire')
+    delete = SubmitField(label='Delete')
diff --git a/models.py b/models.py
new file mode 100644
index 0000000..4bbc2cc
--- /dev/null
+++ b/models.py
@@ -0,0 +1,43 @@
+from datetime import datetime
+from typing import Tuple
+
+
+class RegistrationCode:
+    def __init__(self,
+                 code: str,
+                 creation_time: datetime = datetime.now(),
+                 expiration_time: datetime = None,
+                 usages: int = 0,
+                 max_usages: int = 1):
+        self.code = code
+        self.creation_time = creation_time
+        self.expiration_time = expiration_time
+        self.usages = usages
+        self.max_usages = max_usages
+
+    @staticmethod
+    def from_db(db_registration_code: Tuple) -> 'RegistrationCode':
+        expiration_time = None if db_registration_code[2] is None else datetime.fromisoformat(db_registration_code[2])
+        return RegistrationCode(
+            db_registration_code[0],
+            datetime.fromisoformat(db_registration_code[1]),
+            expiration_time,
+            db_registration_code[3],
+            db_registration_code[4]
+        )
+
+    def is_expired(self):
+        return self.expiration_time is not None and self.expiration_time < datetime.now()
+
+
+class RegisteredUser:
+    def __init__(self, username: str, registered_time: datetime = datetime.now()):
+        self.username = username
+        self.registered_time = registered_time
+
+    @staticmethod
+    def from_db(db_registered_user: Tuple) -> 'RegisteredUser':
+        return RegisteredUser(
+            db_registered_user[0],
+            datetime.fromisoformat(db_registered_user[1])
+        )
diff --git a/requirements.txt b/requirements.txt
index d5443ed..e397b2b 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -1,4 +1,5 @@
 flask==1.0.2
 flask-wtf==0.14
 flask-login==0.4.1
-requests==2.21.0
\ No newline at end of file
+requests==2.21.0
+safe
\ No newline at end of file
diff --git a/schema.sql b/schema.sql
new file mode 100644
index 0000000..00e4806
--- /dev/null
+++ b/schema.sql
@@ -0,0 +1,12 @@
+CREATE TABLE IF NOT EXISTS registration_codes (
+  code VARCHAR(60) NOT NULL UNIQUE,
+  creationTime TIMESTAMP NOT NULL,
+  expirationTime TIMESTAMP,
+  usages INTEGER NOT NULL DEFAULT 0,
+  maxUsages Integer NOT NULL DEFAULT 1
+);
+
+CREATE TABLE IF NOT EXISTS registered_users (
+  username VARCHAR(30) NOT NULL UNIQUE ,
+  registeredTime TIMESTAMP NOT NULL
+);
\ No newline at end of file
diff --git a/templates/admin.html b/templates/admin.html
index 8f0f3f8..6d90cf9 100644
--- a/templates/admin.html
+++ b/templates/admin.html
@@ -5,5 +5,45 @@
 {% endblock %}
 
 {% block content %}
-    <p>ADMIN</p>
+    <div id="activeRegistrationCodes">
+        <table>
+            <thead>
+                <th>Registration Code</th>
+                <th>Creation Time</th>
+                <th>Expiration Time</th>
+                <th>Usages</th>
+                <th>Max Usages</th>
+                <th>Expire</th>
+            </thead>
+            <tbody>
+                {% for registration_code in registration_codes %}
+                    <tr>
+                        <td>{{ registration_code.code|tojson|safe }}</td>
+                        <td>{{ registration_code.creation_time|tojson|safe }}</td>
+                        <td>{{ registration_code.expiration_time|tojson|safe }}</td>
+                        <td>{{ registration_code.usages|tojson|safe }}</td>
+                        <td>{{ registration_code.max_usages|tojson|safe }}</td>
+                        <td>
+                            <form method="POST" action="/admin/expire_registration_code">
+                                <input type="hidden" name="csrf_token" value="{{ csrf_token() }}"/>
+                                <input type="hidden" name="registration_code" value="{{ registration_code.code }}"/>
+                                {% if not registration_code.is_expired() %}
+                                <input type="submit" name="expire" value="Expire">
+                                {% else %}
+                                <input type="submit" name="delete" value="Delete">
+                                {% endif %}
+                            </form>
+                        </td>
+                    </tr>
+                {% endfor %}
+            </tbody>
+        </table>
+    </div>
+    <hr>
+    <form method="POST" action="/admin/add_registration_code">
+        {{ add_registration_code_form.csrf_token }}
+        {{ add_registration_code_form.expiration_time.label }} {{ add_registration_code_form.expiration_time() }}
+        {{ add_registration_code_form.max_usages.label }} {{ add_registration_code_form.max_usages(default="1", value="1") }}
+        <input type="submit" value="Add">
+    </form>
 {% endblock %}
\ No newline at end of file
diff --git a/templates/register.html b/templates/register.html
index 01050d0..23d63b6 100644
--- a/templates/register.html
+++ b/templates/register.html
@@ -9,6 +9,7 @@
         {{ form.csrf_token }}
         {{ form.username.label }} {{ form.username(size=20) }}
         {{ form.password.label }} {{ form.password() }}
+        {{ form.confirm.label }} {{ form.confirm() }}
         {{ form.registration_code.label }} {{ form.registration_code() }}
         <input type="submit" value="Go">
     </form>