Switch to Alpine for Mailcatcher image

mailcatcher/Dockerfile

@@ -1,8 +1,16 @@
-FROM ruby:2.2 
+FROM ruby:2.4-alpine3.6
+
 MAINTAINER Johannes Schickling "schickling.j@gmail.com"
 
-ADD install.sh install.sh
-RUN chmod +x install.sh && ./install.sh && rm install.sh
+RUN set -xe \
+    && apk add --no-cache \
+        libstdc++ \
+        sqlite-libs \
+    && apk add --no-cache --virtual .build-deps \
+        build-base \
+        sqlite-dev \
+    && gem install mailcatcher -v 0.6.5 --no-ri --no-rdoc \
+    && apk del .build-deps
 
 # smtp port
 EXPOSE 1025
@@ -10,4 +18,4 @@ EXPOSE 1025
 # webserver port
 EXPOSE 1080
 
-CMD ["mailcatcher", "-f", "--ip=0.0.0.0"]
+CMD ["mailcatcher", "--foreground", "--ip=0.0.0.0"]

mailcatcher/install.sh

@@ -1,15 +0,0 @@
-#! /bin/bash
-
-# exit if a command fails
-set -e
-
-# install dependencies
-apt-get update && apt-get install -y build-essential sqlite3 libsqlite3-dev
-
-# install mailcatcher
-gem install mailcatcher -v 0.6.5 --no-ri --no-rdoc
-
-# cleanup package manager
-apt-get remove --purge -y build-essential libsqlite3-dev && apt-get autoclean && apt-get clean
-rm -rf /var/lib/apt/lists/* /tmp/* /var/tmp/*
-