Restrict mysql2 version to ~> 0.3.10
Restrict mysql2 version to ~> 0.3.10

ActiveRecord expects mysql2 ~> 0.3.10 (and ~> 0.3.18) to be installed.
Now that mysql2 0.4.x has been released, we need to restrict the
versions of mysql2 that we test against.

This restriction can be relaxed once ActiveRecord is compatible.

wegowise/polymorpheus