Better Docker config: Use entrypoint to setup the environment, run in production mode by default, defaults for all config values

docker-entrypoint.sh

@@ -0,0 +1,17 @@
+#!/bin/bash
+
+export RAILS_ENV=${RAILS_ENV:-production}
+export DATABASE_NAME=${DATABASE_NAME:-tracks}
+export DATABASE_HOST=${DATABASE_HOST:-db}
+export DATABASE_PORT=${DATABASE_PORT:-3306}
+export DATABASE_USERNAME=${DATABASE_USERNAME:-tracks}
+export DATABASE_PASSWORD=${DATABASE_PASSWORD:-password}
+export DATABASE_TYPE=${DATABASE_TYPE:-mysql2}
+export DATABASE_ENCODING=${DATABASE_ENCODING:-utf8}
+
+export RAILS_SERVE_STATIC_FILES=TRUE
+export RAILS_LOG_TO_STDOUT=TRUE
+
+rails db:migrate
+
+exec "$@"