The callback to create the plan at stripe should only happen when the plan is first created, not when it is updated.
Merge pull request #67 from jagthedrummer/jeremy/plan-callback-fix

Stripe plan callback fix
Attempt to fix the ENV load order problem

Lots of users use gems like Dotenv or Figaro to handle their ENV
setup. The problem is that sometimes these gems get loaded after
Payola, which means the secret and publishable keys end up nil.
This patch changes the default secret and publishable keys into
lambdas that get called at the appropriate time, which should
fix the problem.
Removed unnecessary line in change_subscription_plan_spec
updated subscription js forms to pass in quantity
add quantity to async params if subscription is being created
Added change_quantity method to subscriptions_controller
Added old_quantity to Payola::Subscription
quantity_changed event is executed now
quantity is set when subscription is created now
Added change_quantity to routes
Added test for change_quantity, fixed old tests that weren't actually testing anything (the ones testing if they could modify the subscription were always calling cancel, not just change_card and change_quantity)
Added quantity to dummy app form
Added Payola::ChangeSubscriptionQuantity, similar to Payola::ChangeSubscriptionPlan
Added testing for Payola::ChangeSubscriptionQuantity
wrong variable name, changed form to data_form
Added quantity to create_params