Add test to ensure Rails recalculates MP policy agreement percentages
Provide more information for debugging
Reimplement method because there's no primary key for ActiveRecord
Add the beginings of a method to recalculate policy agreement scores
Add an update method we can use without a primary key
Default all values to zero

So we don't encounter nils when performing calculations
Carry out the distance calculations the same as PHP
Add a note about needing to rename these terrible attribute names
Update the calculations after editing a vote
Work around the missing primary key bollocks
Merge branch 'issue153' into test

Conflicts:
	rails/app/models/policy.rb