Use update instead of update_all

`update_all` does not run validations

app/controllers/hackathon/subscriptions/bulk_controller.rb

@@ -7,14 +7,14 @@ class Hackathon::Subscriptions::BulkController < ApplicationController
   # Marking subscriptions as active. Used for undoing an "Unsubscribe from all".
   # PUT /users/:user_id/subscriptions/bulk
   def update
-    @subscriptions.update_all(status: :active)
+    @subscriptions.each(&:resubscribe!)
     redirect_to Hackathon::Subscription.manage_subscriptions_url_for @user
   end
 
   # Marking subscriptions as inactive.
   # DELETE /users/:user_id/subscriptions/bulk
   def destroy
-    @subscriptions.update_all(status: :inactive)
+    @subscriptions.each(&:unsubscribe!)
     redirect_to Hackathon::Subscription.manage_subscriptions_url_for @user
   end
 

app/controllers/hackathon/subscriptions_controller.rb

@@ -18,7 +18,7 @@ def unsubscribe_all
     @subscriptions = @user.subscriptions.active
 
     @unsubscribed_ids = @subscriptions.pluck(:id)
-    @unsubscribe_count = @subscriptions.update_all(status: :inactive)
+    @unsubscribe_count = @subscriptions.map(&:unsubscribe!).count(true)
   end
 
   private

app/models/hackathon/subscription/status.rb

@@ -25,6 +25,14 @@ def unsubscribe_all_url_for(user)
     end
   end
 
+  def unsubscribe!
+    update(status: :inactive)
+  end
+
+  def resubscribe!
+    update(status: :active)
+  end
+
   private
 
   def track_changes