Added tier column to players table

Eventually, we'll probably want different tiers, but this is a good place to start I think
Added some more notes to the readme
Just a bit of formatting for the README
I should learn rdoc better
Adding ai4r

Provides lots of AI algorithms.

Using for clustering now, but I imagine we'll use
some ML or classifiers in the future too
First commit of clustering code.

Just does basic clustering.  No tuning, and no attempt to rank
clusters, so we know which tier is 'better' than the other.

Also, is only using the total_points to cluster.

Would be trivial to add more dimentions to the data, rather than
just using the total.
Use new tiers in index view
Added running rake api:tier to the instructions
A bit of tuning
Sort the tiers by average total points
Turns out ai4r will do the mean for you
Just cleaning whitespace
Added a tier column, for helping to debug
xs
Merge pull request #4 from rationalcarl/will-clustering-tiers

Will clustering tiers