feat(billings): add strong params

app/controllers/billing_subscriptions_controller.rb

@@ -34,4 +34,10 @@ class BillingSubscriptionsController < ApplicationController
     @billing_plan = @nonprofit.billing_plan
     @billing_subscription = @nonprofit.billing_subscription
   end
+
+  private
+
+  def required_params
+    params.permit(:nonprofit_id, :billing_plan_id, :stripe_subscription_id, :status)
+  end
 end

app/models/billing_plan.rb

@@ -2,11 +2,6 @@
 
 # License: AGPL-3.0-or-later WITH Web-Template-Output-Additional-Permission-3.0-or-later
 class BillingPlan < ApplicationRecord
-  Names = ['Starter', 'Fundraising', 'Supporter Management'].freeze
-  DefaultAmounts = [0, 9900, 29_900].freeze # in pennies
-
-  # TODO
-  # attr_accessible \
   # :name, #str: readable name
   # :tier, #int: 0-4 (0: Free, 1: Fundraising, 2: Supporter Management)
   # :amount, #int (cents)
@@ -14,6 +9,9 @@ class BillingPlan < ApplicationRecord
   # :interval, #str ('monthly', 'annual')
   # :percentage_fee # 0.038
 
+  Names = ['Starter', 'Fundraising', 'Supporter Management'].freeze
+  DefaultAmounts = [0, 9900, 29_900].freeze # in pennies
+
   has_many :billing_subscriptions
 
   validates :name, presence: true

app/models/billing_subscription.rb

@@ -2,8 +2,6 @@
 
 # License: AGPL-3.0-or-later WITH Web-Template-Output-Additional-Permission-3.0-or-later
 class BillingSubscription < ApplicationRecord
-  # TODO
-  # attr_accessible \
   # :nonprofit_id, :nonprofit,
   # :billing_plan_id, :billing_plan,
   # :stripe_subscription_id,