Add separate last_login column to users model

backend/app/controllers/application_controller.rb

@@ -28,7 +28,7 @@ def user_locale
 
   def set_last_login
     if current_user
-      current_user.touch
+      current_user.update_columns(last_login: Time.current)
     end
   end
 

backend/app/models/user.rb

@@ -16,10 +16,6 @@ class User < ActiveRecord::Base
   validates :email, uniqueness: true, if: proc { |u| u.email.present? }
   validates :auth0_uid, uniqueness: true, if: proc { |u| u.auth0_uid.present? }
 
-  def last_time_user_was_active
-    impressions.order(updated_at: 'desc').first&.updated_at || updated_at
-  end
-
   def self.from_token_payload(payload)
     if payload['sub'].blank?
       nil

backend/db/migrate/20180719134105_add_last_login_to_user.rb

@@ -0,0 +1,5 @@
+class AddLastLoginToUser < ActiveRecord::Migration[5.1]
+  def change
+    add_column :users, :last_login, :datetime
+  end
+end