Add database support

[calebmeyer]

The current application has nothing in schema.rb, no migrations, and no host defined in the database.yml

I assume there's some work to be done to ensure that docker can talk to a database run

• locally at 0.0.0.0
• in another container
• somewhere that DNS can resolve (like database.mywebsite.com)

The "in another container" solution seems the best from the perspective of running everything needed locally using docker. However, this presents challenges:

• How do we get the schema loaded? Do we do this every time?
• How do we seed the initial data? Do we do this every time?
• Can we keep a local copy of our data, or is the database refreshed every time?

Can we get that included?

[mikeantonelli]

Hi @calebmeyer. I think this would also be a useful example to include. I've done this a few different ways in the past.

• Create a new service in our docker-compose.yml, call it db and just run the community mysql image
• Add depends_on to services you want to spin up the database for first.
• Create a utility service that overrides app with database commands.

I imagine it would look something like:

services:
  db-migrate:
    command: sh -c "bundle exec rake db:migrate"
    depends_on:
      - db
    environment:
      - DB_HOST: db
    image: 'mikeantonelli/docker-rails-compose:${VERSION-latest}'

  db:
    image: 'mysql:5.6'

Rather than build a new image varient, I would think that our production image should have all schema, migrations, and db connection configuration. It might also be a good time to introduce env_files instead of environment in service definitions so that we can take advantage of the same database configuration for db, db-migrate and app.

The result would be the capability to:

docker-compose run db-migrate

You could also override this to run custom commands:

docker-compose run db-migrate sh -c 'bundle exec rake db:setup`

So, maybe a different name than db-migrate makes more sense?

I also think we could update the app front end to show the current migration version so there was an example of database utilization in the project.

[mikeantonelli]

@calebmeyer I opened #4 if you want to take a look.