Added shared contexts for testing

- bag of words
- request
Support to visualize multiple environments db
Fixed missing 'new' variable bug and refactored
Added support for date detection in pages
New bag of words structure.

Added controller to handle it
Added module 'relevance'
Added specification for bag of words
Modified dossier endpoint to cover all these changes
Refactored newspaper mock. Now standalone and runnable from within the tests!!
Added management of bag of words spec
Refactored process new from crawler spec.

Uses the shared contexts and the mock newspaper, it focus on the important: search news and assert there is 1 new.
Added endpoint to add a word to the bag of words and modified command to not start the search in case there are no words in the bag
Remove require "relevance functionality" from news controller
Refactor spec helper and dossier rb. 

It uses the RACK_ENV environment to determine which environment to load. 
Added configuration for test environment.
Updated crawl command specification. 

By default is false, the crawler is not working