Use MySQL as the database

[mjstallard]

As we are standardizing on using MySQL for Pivotal apps hosted on Cloud Foundry, we are changing Project Monitor to use this instead of Postgres.

• MySQL doesn't support default values for TEXT fields, so we default the value of Project#iteration_story_state_counts in Ruby
• turns out that MySQL's precision for datetime values is less than Postgres, so we have to fiddle the created_at value in some tests
• MySQL doesn't support RANK() OVER(PARTITION BY... style queries, so this has been replaced by a query based on this Stackoverflow article

I will update this Pull Request once we're running this in production.

[mjstallard]

We can confirm that this is now in production - see http://ci.pivotallabs.com/

[tjgrathwell]

@erd @mjstallard re: 043d0de - I don't see the 'simplifying', it looks like you just deleted both the manifests?

Is there a unified ultra-manifest sitting around that you didn't add to git?

If you changed the command used to deploy, https://github.com/pivotal/projectmonitor#deployment should be updated too

[erd]

Whoops... yeah, there's a manifest in the root directory that we forgot to add. We'll fix it up tomorrow (and include a doc update).

[erd]

We've added a workaround for the emoji by using serialize for the project's code field. This will cause the field to roundtrip to Marshal, allowing it to be persisted in spite of MySQL.

See https://dev.firmafon.dk/blog/quick-no-hack-emoji-support-with-mysql-rails/ for more details.

This is a quicker/easier way of doing things, rather than adding full emoji support for every table by migrating to utf8mb4.

[professor]

I'm curious about the status of this pull request. I've seen emoji's on pulse monitor. Do we still want this code?

[mjstallard]

Closing this as I no longer work at Pivotal and I think this is a pretty stale PR by now 🙃