move invalidating Redis to after_create and after_update hooks

app/controllers/registration_controller.rb

@@ -138,9 +138,6 @@ def process_update(update_request)
       EmailApi.send_update_email(@competition_id, user_id, status, @current_user)
     end
 
-    # Invalidate cache
-    Rails.cache.delete("#{user_id}-registrations-by-user")
-
     {
       user_id: updated_registration['user_id'],
       guests: updated_registration.guests,

app/jobs/registration_processor.rb

@@ -17,7 +17,6 @@ def perform(message)
                          message[:created_at],
                          side_effects)
     end
-    Rails.cache.delete("#{message[:user_id]}-registrations-by-user")
     side_effects.run(:after_processing)
     Metrics.increment('registrations_processed')
   end

app/models/registration.rb

@@ -14,6 +14,10 @@ class Registration
   # Pre-validations
   before_validation :set_competing_status
 
+  # Hooks
+  after_create :delete_user_registration_from_redis
+  after_update :delete_user_registration_from_redis
+
   # Validations
   validate :competing_status_consistency
 
@@ -216,4 +220,8 @@ def waiting_list_status_changed?(update_params)
       states_are_different = competing_status != update_params[:status]
       lane_state_present && states_are_different
     end
+
+    def delete_user_registration_from_redis
+      RedisHelper.delete_user_registrations(user_id)
+    end
 end

lib/redis_helper.rb

@@ -9,6 +9,10 @@ def self.increment_or_initialize(key, &)
     end
   end
 
+  def self.delete_user_registrations(user_id)
+    Rails.cache.delete("#{user_id}-registrations-by-user")
+  end
+
   def self.decrement_or_initialize(key, &)
     if Rails.cache.exist?(key)
       Rails.cache.decrement(key)