Merge pull request #34 from jbwhite/minorFix

added @user definiton to layout view to stop throwing errors for undefin...
tag select for topic working
add tag select for comments
tag selection for comments/topics seems to work, needs more testing
removed Tagations from seed file, added checks for @user to avoid errors on homepage
set Comment/show route to got to Topic show page that comment belongs to:
tag tests look good
Merge branch 'master' into joseph