feat(promotion code): Promotion code system done

I added the features for users to use promotion code
and for promoters to create on their events.
May be rewrite to discount code?

db/seeds.rb

@@ -280,3 +280,26 @@ TicketType.find_or_create_by!(event: belle_epoque_october_event, name: "Entry 10
 end
 
 puts "Created 3 additional events from Bizouk with ticket types"
+
+# Create promotion codes for events
+# Promotion code for belle_epoque_event
+PromotionCode.find_or_create_by!(code: "BELLE10") do |pc|
+  pc.discount_amount_cents = 1000  # 10€ discount
+  pc.expires_at = belle_epoque_event.start_time + 1.day
+  pc.active = true
+  pc.usage_limit = 20
+  pc.user = promoter
+  pc.event = belle_epoque_october_event
+end
+
+# Promotion code for belle_epoque_october_event
+PromotionCode.find_or_create_by!(code: "OCTOBRE5") do |pc|
+  pc.discount_amount_cents = 500  # 5€ discount
+  pc.expires_at = belle_epoque_october_event.start_time + 1.day
+  pc.active = true
+  pc.usage_limit = 30
+  pc.user = promoter
+  pc.event = belle_epoque_october_event
+end
+
+puts "Created promotion codes for events"