Added RSpec and FactoryGirl gems
Installed RSpec
Removed fixtures from spec helper
Added shoulda gem
Added polymorphic association to Order
Fixed a typo
Added factory and unit test for User model
Fixed polymorphic association
Added factories for Customer, Supplier and Membership
Added Customer model spec
Added #members to Supplier model
Added Supplier model spec
Added Membership model spec
Added Travis configuration
Fixing Travis conf
Added ERD gem
Added models png diagram in docs
Add ERD image to readme
Removed orders association from user
Fixed Orders associations