Spam detection

Reference Issue #75 

@AminaZoheir and @linabasheer reviews?

Only `config/initializers/bot-away.rb` contains any documentation.

Tests and UML are missing. Will be pushed shortly.

Scenario is a little difficult to review. One has to turn on the gem in development mode from `config/initializers/bot-away.rb` then go to any of the forms (such as idea creation or comments) and try to fill one of the hidden honeypot fields by unhiding them.