Remove link to thoughtbot's style guide on homepage

Having a link to thoughtbot's style guide obscures that hound is
configurable.

https://github.com/thoughtbot/hound/issues/203
https://trello.com/c/wYwsF46g
Minor rule updates

* Test method chaining
* Enable IndentationConsistency rule
* Remove remaining pending tests
Test named arguments
add timestamps to repos and memberships
Add index for remember_token in users
Add index for github_id in repos
Add index to repos for active
Make github_id index unique