Update the Docker image for easier use of automated builds

Signed-off-by: Travis Ralston <travpc@gmail.com>

.dockerignore

@@ -0,0 +1,10 @@
+vendor/pkg
+vendor/src
+pkg
+hooks
+bin
+
+# Other stuff we just don't need
+.gitignore
+.git
+.travis.yml

Dockerfile

@@ -2,7 +2,18 @@ FROM alpine:3.6
 
 ENV BIND_ADDRESS=:4050 DATABASE_TYPE=sqlite3 DATABASE_URL=/data/go-neb.db?_busy_timeout=5000
 
-COPY bin/go-neb /go-neb
+COPY . /tmp/go-neb
+WORKDIR /tmp/go-neb
+ENV GOPATH=/tmp/go-neb/vendor/src:/tmp/go-neb/vendor:/tmp/go-neb
+RUN apk add --no-cache -t build-deps git gcc musl-dev go \
+    && go get -u github.com/constabulary/gb/... \
+    && export PATH="/tmp/go-neb/vendor/src/bin:${PATH}" \
+    && gb vendor restore \
+    && gb build -f github.com/matrix-org/go-neb \
+    && mv bin/go-neb /go-neb \
+    && cd / \
+    && rm -rf /tmp/* \
+    && apk del build-deps
 
 VOLUME /data
 EXPOSE 4050

README.md

@@ -225,7 +225,7 @@ sensible-browser http://localhost:6060/pkg/github.com/matrix-org/go-neb
 
 ## Docker image
 
-There is a `Dockerfile` in the root of the repository and a `build-docker-image.sh` script that uses an alpine-based golang container to build `go-neb` (note that this will overwrite host-built binaries in `pkg/` and `bin/`) and then builds the docker image using that binary.
+There is a `Dockerfile` in the root of the repository which copies the local source files and builds go-neb.
 
 The image sets the following environment variables:
 ```

build-docker-image.sh

@@ -1,12 +0,0 @@
-#!/bin/bash
-
-set -e
-
-docker run \
-    --rm \
-    -v "$PWD":/usr/src/myapp \
-    -w /usr/src/myapp \
-    golang:1.8-alpine \
-    sh -c 'apk add --no-cache git gcc musl-dev && go get -u github.com/constabulary/gb/... && gb build -f github.com/matrix-org/go-neb'
-
-docker build -t ${IMAGE_PREFIX}go-neb:latest .