Remove extra blank lines
Missing space after #
Space bwtween { and | missing
Remove space inside parentheses
Remove space inside square brackets
Missing space after comma
Missing space inside }
Space missing to the left of {
Surround operators with spaces
Add underscores to large numeric literals
Prefer until over where

unless the conditional contains an assignment
Never use unless with an else

Rewrite the positive case first
Prefer map over collect
Prefer single quotes without interpolation
Prefer Ruby 1.9 style syntax