detect Mongoid (till Mongoid will implement it) (#1348)

Author: exocode

app/models/devise_token_auth/concerns/user.rb

@@ -214,7 +214,7 @@ def destroy_expired_tokens
   end
 
   def should_remove_tokens_after_password_reset?
-    if Rails::VERSION::MAJOR <= 5
+    if Rails::VERSION::MAJOR <= 5 || defined?(Mongoid)
       encrypted_password_changed? &&
         DeviseTokenAuth.remove_tokens_after_password_reset
     else