O295: Sponsorship start_date validation - must be Date format +rspec and cucumber
O296: Sponsorship start_date validation: not later than the first of next month +rspec and cucumber tests
refactoring: rspec and cucumber tests and more
Merge pull request #224 from razorcd/O295andO296_sponsorship_start_date_validation

OSRA-295 OSRA-296 #Resolved
Model Sponsorship end_date validation + rspec tests
rebase, solved conflicts