trying to create many to many relationship for tags with has_and_belongs_to_many
Merge branch 'develop' into issue_5

Conflicts:
	app/models/cyte.rb
	db/schema.rb
	spec/factories/cytes.rb
	spec/models/cyte_spec.rb
Merge branch 'develop' into issue_5

Conflicts:
	app/models/cyte.rb
	db/schema.rb
	spec/factories/cytes.rb
	spec/models/cyte_spec.rb
tags and cytes
issue 5 (tags)
- added tags
- fixed hierarchical comments
- refactored factories
added default task to Rakefile to prevent Travis fail
Rename Tag.rb to tag.rb
Merge pull request #10 from LambdaTeamAtBursa/issue_5

Model for tags, and some refactorings