Fix/position

The octokit api expects position, not line number, which is what you are giving it, however this keeps it all named the same.

I also updated the readme with a step I needed to get it running locally.

This all passes except [this test](https://github.com/thoughtbot/hound/issues/311) which failed on a clean slate.
It created both databases, but it didn't create the test tables which caused the tests to fail for me. It just created the tables in `development`.
![07_07_14 at 12 36 18pm](https://cloud.githubusercontent.com/assets/769039/3499192/4d17e25c-05fd-11e4-82ed-6e1201876ef8.png)