Simplify and fix docker builder

Dockerfile

@@ -1,26 +1,10 @@
-FROM ubuntu:trusty
-MAINTAINER Paul Bowsher <paul.bowsher@gmail.com>
+FROM ruby:2.3
+MAINTAINER Samuel Cochran <sj26@sj26.com>
 
-RUN apt-get update && apt-get install -y -q \
-    build-essential \
-    git \
-    libssl-dev \
-    libsqlite3-dev \
-    nodejs \
-    ruby-dev \
-    sqlite3 \
- && apt-get clean \
- && rm -r /var/lib/apt/lists/* \
- && gem install bundler --no-ri --no-rdoc
-
-ADD . /app
-WORKDIR /app
-
-RUN bundle install
-RUN bundle exec rake assets
+RUN gem install mailcatcher
 
 EXPOSE 1025
 EXPOSE 1080
 
-ENTRYPOINT ["bundle", "exec", "mailcatcher", "-f"]
+ENTRYPOINT ["mailcatcher", "-f"]
 CMD ["--ip", "0.0.0.0"]