[dm-types] Declare auto validations in Types::Enum.bind, because this is what .bind is for.
[dm-types] Declare auto validations in Types::Enum.bind, because this is what .bind is for.

 * If your type needs to extend model somehow, consider using .bind and NOT aliasing.
 * When multiple plugins use aliasing at the same time, it's like a perfect storm of failures

troygnichols/dm-types,ar-dm/ardm-types,lgierth/dm-types,engineyard/dm-types,datamapper/dm-types