Fix for breaking development_seeds.rb

It was trowing this error:

`
/Users/Guga/.rbenv/versions/2.1.3/lib/ruby/gems/2.1.0/gems/activerecord-4.1.5/lib/active_record/validations.rb:57:in 'save!': Validation failed: User can't be blank (ActiveRecord::RecordInvalid)
`