solve code reviews, resolve rebase conflicts

app/models/payment.rb

@@ -36,30 +36,25 @@ class Payment < ActiveRecord::Base
 
   def purchase(user, conference, price_in_cents)
     begin
-      response = GATEWAY.purchase(price_in_cents, credit_card, currency: conference.tickets.first.price_currency)
+      recieve = GATEWAY.purchase(price_in_cents, credit_card, currency: conference.tickets.first.price_currency)
     rescue
       false
     end
 
-    unless response
+    unless recieve
       errors.add(:base, 'Unable to recieve any response')
       return false
     end
-    unless response.success?
-      errors.add(:base, response.message)
+    unless recieve.success?
+      errors.add(:base, recieve.message)
       self.status = 'failure'
       return false
     end
     self.user_id = user.id
     self.conference_id = conference.id
     self.last4 = credit_card.display_number
-    self.authorization_code = response.authorization
+    self.authorization_code = recieve.authorization
     self.status = 'success'
-    response.success?
-  end
-
-  # method to test `purchase` method
-  def self.make_payment(user, conference, price_in_cents, payment)
-    payment.purchase(user, conference, price_in_cents)
+    recieve.success?
   end
 end

app/models/ticket.rb

@@ -18,18 +18,12 @@ class Ticket < ActiveRecord::Base
   end
 
   def paid?(user)
-    ticket_purchases.find_by(user: user, paid: true).present?
+    ticket_purchases.paid.by_user(user).present?
   end
 
   def quantity_bought_by(user, paid: false)
-    purchased_tickets = ticket_purchases.where(user_id: user.id, paid: paid)
-    quantity = 0
-    if purchased_tickets
-      purchased_tickets.each do |ticket|
-        quantity += ticket.quantity
-      end
-    end
-    quantity
+    purchased_tickets = ticket_purchases.paid.by_user(user)
+    quantity = purchased_tickets.sum(:quantity)
   end
 
   def unpaid?(user)

app/models/ticket_purchase.rb

@@ -13,7 +13,10 @@ class TicketPurchase < ActiveRecord::Base
   delegate :price_cents, to: :ticket
   delegate :price_currency, to: :ticket
 
+  scope :paid, -> { where(paid: true) }
   scope :unpaid, -> { where(paid: false) }
+  scope :by_conference, -> (conference) { where(conference_id: conference.id) }
+  scope :by_user, -> (user) { where(user_id: user.id) }
 
   def self.purchase(conference, user, purchases)
     errors = []