Devise: confirm user email

db/migrate/20180514091001_add_confirmable_to_user_devise.rb

@@ -0,0 +1,18 @@
+class AddConfirmableToUserDevise < ActiveRecord::Migration[5.2]
+  def up
+    add_column :users, :confirmation_token, :string
+    add_column :users, :confirmed_at, :datetime
+    add_column :users, :confirmation_sent_at, :datetime
+    add_index :users, :confirmation_token, unique: true
+    # User.reset_column_information # Need for some types of updates, but not for update_all.
+    # To avoid a short time window between running the migration and updating all existing
+    # users as confirmed, do the following
+    User.all.update_all confirmed_at: DateTime.now
+    # All existing user accounts should be able to log in after this.
+  end
+
+  def down
+    remove_columns :users, :confirmation_token, :confirmed_at, :confirmation_sent_at
+    # remove_columns :users, :unconfirmed_email # Only if using reconfirmable
+  end
+end