Move bundle installation to entrypoint script

Makes it one step less you have to do in the dev-env setup.

CONTRIBUTING.md

@@ -27,14 +27,19 @@ based development environment, based on [docker](https://www.docker.com/) and
 [docker-compose](https://docs.docker.com/compose/). Here's a step by step guide
 how to set it up.
 
-1. Set up the development environment:
-    ```bash
-    docker-compose run --rm osem bundle exec rake setup:bootstrap
-    ```
+**WARNING**: Since we mount the repository into our container, your user id and
+the id of the osem user inside the container need to be the same. If your user
+id (`id -u`) is something **other** than `1000` you can copy the docker-compose
+override example file and in it, set your user id in the variable
+*CONTAINER_USERID*.
 
-1. Start the development environment:
+```bash
+cp docker-compose.override.yml.example docker-compose.override.yml
+```
+
+1. Start the development environment¹:
     ```bash
-    docker-compose up --build
+    docker-compose up
     ```
 
 1. Check out your OSEM rails app. You can access the app at http://localhost:3000. Whatever you change in your cloned repository will have effect in the development environment. Sign up, the first user will be automatically assigned the admin role.
@@ -54,13 +59,6 @@ how to set it up.
     docker-compose exec osem_1 /bin/bash -l
     ```
 
-**WARNING**: Since we mount the repository into our container, your user id and the id of the osem user inside the container need to be the same. If your user id (`id -u`) is something else than `1000` you can copy the docker-compose override example file and in it, set your user id in the variable
-*CONTAINER_USERID*.
-
-```bash
-cp docker-compose.override.yml.example docker-compose.override.yml
-```
-
 ### with Vagrant
 Another option is using [Vagrant](https://www.vagrantup.com/) and [VirtualBox 5.0.10](https://www.virtualbox.org/wiki/Download_Old_Builds_5_0) to create your development environment.
 

Dockerfile

@@ -4,19 +4,8 @@ ARG CONTAINER_USERID
 # Configure our user
 RUN usermod -u $CONTAINER_USERID osem
 
-# We copy the Gemfiles into this intermediate build stage so it's checksum
-# changes and all the subsequent stages (a.k.a. the bundle install call below)
-# have to be rebuild. Otherwise, after the first build of this image,
-# docker would use it's cache for this and the following stages.
-COPY Gemfile /osem/
-COPY Gemfile.lock /osem/
-RUN chown -R osem /osem
-
-# Add our files
 USER osem
 WORKDIR /osem/
 
-# Install our bundle
-RUN export NOKOGIRI_USE_SYSTEM_LIBRARIES=1; bundle install --jobs=3 --retry=3
+CMD ["/osem/bin/osem-init.sh"]
 
-CMD ["foreman", "start"]

bin/osem-init.sh

@@ -1,3 +1,9 @@
 #!/bin/bash
+# Configure our bundle
+export NOKOGIRI_USE_SYSTEM_LIBRARIES=1
+# Install our bundle if it's outdated
+bundle check || bundle install --jobs=3 --retry=3
+# Setup the app if it isn't already setup
 bundle exec rake setup:bootstrap
+# Start the app
 foreman start