Support null database driver

[nickmarden]

Fixes #98

TODO:

• Write integration tests
• Add documentation

[coveralls]

Coverage remained the same at 100.0% when pulling c4c71b6 on RapidRiverSoftware:nick/null-database-adapter into 5568f6c on ajgon:master.

[ajgon]

👍
One thing though - can you create an integration test for that?

[coveralls]

Coverage remained the same at 100.0% when pulling ccb8665 on RapidRiverSoftware:nick/null-database-adapter into 89ce561 on ajgon:master.

[nickmarden]

@ajgon This is worth pointing out. In my attempts to create an integration test with a very simple Rails app (no DB even!) I needed these two packages libxml2-dev and tzdata because they are core requirements of Rails 4.x. I think it makes sense to add them here because (a) everyone needs them and (b) they are very standard libraries for the servers that people will be building using opsworks_ruby anyway.

[nickmarden]

To satisfy your request for integration tests, I learned me up some Chef Kitchen and created the maximum_override suite. I will now rebase my other pull requests one at a time on top of this PR to add integrations tests for the other "override" behaviors (overriding site configs, overriding logrotate, using passenger as an application loader, etc.) that I have introduced in my PRs.

Of course this means that my PRs will need to be merged in order, but ¯_(ツ)_/¯ we were going to have to merge them in some order anyway!

[coveralls]

Coverage remained the same at 100.0% when pulling 29e1040 on RapidRiverSoftware:nick/null-database-adapter into 89ce561 on ajgon:master.

[coveralls]

Coverage remained the same at 100.0% when pulling 29e1040 on RapidRiverSoftware:nick/null-database-adapter into 89ce561 on ajgon:master.