Merge pull request #27 from alim/Issue_26

Issue 26 - Adding tag attributes for ImmuneResponse and Macrophage classes.
Issue #29 - Updates to show group names in User#show view
Merge pull request #31 from alim/Issue_29

Issue #29 - Updates to show group names in User#show view
Issue #26 - Adding taggable feature
Issue #26 - Updates to tagging using new mongoid_taggable GEM