Use separate db for testing

Here is wrapper that connects to separate, testing db.
It should simplify writing tests: instead of cleanup at the end of the spec - 'flushdb' could be used.
Even more - since production db isn't touched - user can run tests in production to verify successful code update, for example.

I'm not sure about two things:
1. Placement of `mocks` directory, mb it should be merged with tests or fixtures in `install`?
2. Seeding during installation - I have added few more steps, that new developer wouldn't have to create config manually. But it could be confusing for regular users.