Update Gemfile.lock with rake
Test api_key is required when making requests (pending)
Test Order.create returns new Order object
Return new Order
Test api url returned from Order.url
Return API URL base from Zinc module
Return order API URL in Order.url
Clarify test name
Test Zinc.response returns valid response object
Create framework for test requests
Send requests through to execute_request
Make request if params are not empty
Add functions to return sample JSON for creating order
Test creating order object
Use method_missing to return values from internal hash in Order object
Use empty block to mark test as implemented

Is there a better way to structure this code so the @mock assertions
will be explicit?
Enable check that request with no api key throw exception
Add Zinc::AuthenticationError
Require AuthenticationError
Define Zinc api_key class variable