Include current user in list of followers shown when I use '@'

Feedback from jkatz:

I often find myself @mentioning myself, and it takes longer than it should. In edit mode, when I click "@", it pre-populates with a list of people that I follow. Now, the list includes myself. It's been 2 weeks, and I've found it useful on multiple occasions. Perhaps listing the user in this list should be the default.

If we add the current user, people won't have to follow themselves