This is a mergeable idea/pattern. Posting as pull request to gather feedback.
This is a step towards removing global mocks. In a test instead of
mocking the global "database.Mocks.Repos.List", you will pass in a
"RepoStore" with "rs.Mock.List" set.
I quite like this pattern, since it avoids interfaces but gives you the
benefit of mocking. As we move to passing around RepoStore more it will
start to bare fruit (right now we seem to pass around db a lot, instead
of the stores).
My preference of mocking this way is if a service uses a RepoStore, it
can directly store a "*RepoStore" in its struct rather than an
interface. This allows static analysis tools (find references, rename,
etc) to continue to function.
