Users can suggest tags on links

[elubow]

This doesn't mean that they will immediately get added. This just means that the tags will go into a suggestion queue and then a moderator/admin will go through them and approve/disapprove them as necessary

Implement this by adding modal on all the link#show pages called suggestions. It loads up a text box with the tag selection autocomplete (chosen) and loads up the tags. User types in those tags and it goes to a suggestion model which has a state machine(:pending, :rejected, :accepted). If accepted, it makes the change and updates the link history model. If rejected, then change state to allow for filtering.