Merge pull request #2 from georgexzeng/master

finish models, migrations and routes
Merge pull request #3 from georgexzeng/master

finish implementing views for topics
Merge pull request #4 from georgexzeng/master

finish comments controller and views; add edit for articles
create tag and tagation models
updated seed file to add tags and tagations, removed validations from user
tag and tagation models complete
Merge branch 'master' into tags
Merge pull request #5 from jbwhite/tags

Tags
Merge pull request #7 from georgexzeng/master

integrated stephen's changes and resolved merge conflicts