Test on Rails 4.2.x beta
Fix input tests due to attributes order

Rails decided to trade output consistency for speed, removing the
attributes sorting when generating tags. This means now tags will be
generated based on the order of the passed hash.

https://github.com/rails/rails/commit/03d30ce71ca17cec82774a86d2acc87e2f153e53
Fix decimal and type casting failures

Precision/scale are needed on the schema due to bigdecimal type casting
now, and the string column account_number is properly type casted to
string when setting the attribute, so just compare to string all the
time.