WIP: Populate league with default teams

@ShaiNirShado 

I'm starting with a spec to fill a new league with 22 teams (20 players, 1 commish, 1 user.). So far, so good, but I'm not sure how to add the 'type'. I may as well also add here that if I were to change Special column to Type or something of the, sort, do I just ned to change the model and then rebuild the database?

Next step after this is to apply similar methods to make 22 default teams in a league. I'm going to assume the league owner will be able to change their names as he sees fit. Do we want to use the default MLB teams here?
21 is a 'magic number' here. We're ultimately going to make this number configurable. For now, please move it to a constant at the top of the file so we can find it easier.