Tech - Doctors: Fix memory overuse on github push request [#52303595]

Pivotal tracker story [#52303595](http://www.pivotaltracker.com/story/show/52303595) in project *Tech - Doctors*:

> NoMemoryError - failed to allocate memory:
>  /mnt/app/integrity/shared/bundle/ruby/1.8/gems/dm-validations-1.2.0/lib/dm-validations/validators/length_validator.rb:100:in `scan'
>  /mnt/app/integrity/shared/bundle/ruby/1.8/gems/dm-validations-1.2.0/lib/dm-validations/validators/length_validator.rb:100:in `value_length'
>  /mnt/app/integrity/shared/bundle/ruby/1.8/gems/dm-core-1.2.0/lib/dm-core/resource.rb:1005:in `_save
> ...