repair code reviews, improve environment configs

app/models/ability.rb

@@ -81,7 +81,7 @@ class Ability
 
     can :index, Ticket
     can :manage, TicketPurchase, user_id: user.id
-    can :manage, Payment, user_id: user.id
+    can [:new], Payment, user_id: user.id
 
     can [:create, :destroy], Subscription, user_id: user.id
 

app/models/ticket.rb

@@ -26,7 +26,7 @@ class Ticket < ActiveRecord::Base
   end
 
   def unpaid?(user)
-    ticket_purchases.find_by(user: user, paid: false).present?
+    ticket_purchases.unpaid.by_user(user).present?
   end
 
   def total_price(user, paid: false)