Now with memory!

I should have committed more often in this process, but I was on a roll.
Create watched episodes table to track how long users have watched episodes.
Create watched episodes controller
Create watched episodes model
Users have many watched episodes
Episodes have many watched episodes
Watched episodes belong to Users and Episodes (db has index on both ids)
Add create route and action for watched episodes.
Add watched episode form to media players
Add javasript listener for timeupdate on player to submit timecodes
Probably a few other little things I can't remember now
Add checks for current user when grabbing watched episodes
Navigation link wording changes