suggestion:
Make a static controller with a single action called home. Then make sure the root route is set correctly

Complete the has_many associations for tags

Suggestion: do not nest things under the user unless your intent is to give access to see other users' entries. If that is not necessary, then neither is nesting anything under the user. You can use current_user instead, to get the value of the user, rather than adding it to the url params.

might want to nest new and index comments under a resourze, or possibly tags.

What scope method should we implement?
Something like 5 most recent comments?
Most used tags