Revert "PERF: Query for email was not using index."

This reverts commit 65eb046e69.

app/models/user.rb

@@ -134,9 +134,7 @@ class User < ActiveRecord::Base
   # set to true to optimize creation and save for imports
   attr_accessor :import_mode
 
-  scope :with_email, ->(email) do
-    joins(:user_emails).where("lower(user_emails.email)::text = ?", email)
-  end
+  scope :with_email, ->(email) { joins(:user_emails).where(user_emails: { email: email }) }
 
   scope :human_users, -> { where('users.id > 0') }