tagging: added some backend logic to create and retrieve tags.  made changes to the migration files
trying to fix some Hound errors
hound errors
hound errors
setting association between tag and assignment
hound
removing user association and assignments association in migration files
removing associations from model files
remove assignment methods, added one grouping method
hound spacing
Merge pull request #1863 from nathanychow/tagging

tagging: added some backend logic to create and retrieve tags.  made cha...