Fix the Docker Compose configuration and remove the database config from VCS

Fixes #2248.

Dockerfile

@@ -5,8 +5,6 @@ RUN bundle config --global frozen 1
 
 WORKDIR /app
 
-RUN touch /etc/app-env
-
 COPY Gemfile* /app/
 RUN gem install bundler
 RUN bundle install --jobs 4

config/database.yml

@@ -1,32 +0,0 @@
-development:
-  adapter: mysql2
-  database: tracks
-  # set this if you are storing utf8 in your mysql database to handle strings
-  # like "Réné". Not needed for sqlite. For PostgreSQL use encoding: unicode
-  # encoding: utf8
-  host: db
-  username: root
-  password:
-
-test:
-  adapter: mysql2
-  database: tracks_test
-  # set this if you are storing utf8 in your mysql database to handle strings
-  # like "Réné". Not needed for sqlite. For PostgreSQL use encoding: unicode
-  # encoding: utf8
-  host: db
-  username: root
-  password:
-
-# Production config is disabled by default
-#
-# production:
-#  adapter: mysql2
-#  database: tracks
-#  # set this if you are storing utf8 in your mysql database to handle strings
-#  # like "Réné".Not needed for sqlite. For PostgreSQL use encoding: unicode
-#  # encoding: utf8
-#  host: localhost
-#  username: root
-#  password:
-

docker-compose.yml

@@ -9,6 +9,8 @@ services:
       - db-data:/var/lib/mysql
   web:
     build: .
+    environment:
+      DATABASE_USERNAME: root
     volumes:
       - ${VOLUME:-.:/app}
     ports: