add NewComment() for adding comments to advisories
add process queue for advisory
add Connector interface, finish process queue
Remove UserIP and UserToken - leave that to the frontend
Implement User, remove UserIP and UserToken (frontend can do that)
close the queue to signal we're finished
Add testsuite

...which naturally fixes a hell of a lot of problems with initial
code, of course. A few nitpicks with GORM - see FIXME comments.