Migrate pricing rules controller to strong parameters

Author: mayorova

app/controllers/api/pricing_rules_controller.rb

@@ -76,6 +76,6 @@ def authorize_action
   end
 
   def pricing_rule_params
-    params.require(:pricing_rule)
+    params.require(:pricing_rule).permit(:min, :max, :cost_per_unit)
   end
 end

app/models/pricing_rule.rb

@@ -5,8 +5,6 @@ class PricingRule < ApplicationRecord
   belongs_to :plan
   belongs_to :metric
 
-  attr_protected :metric_id, :plan_id, :plan_type, :tenant_id, :audit_ids
-
   # TODO: add validations that check that the intervals are well defined. TODO:
   # min must be always > 0
   #