correct user passwd and sent json to front-end

app/controllers/desktop/registrations_controller.rb

@@ -0,0 +1,15 @@
+class Desktop::RegistrationsController < Devise::RegistrationsController
+  def update
+    self.resource = resource_class.to_adapter.get!(send(:"current_#{resource_name}").to_key)
+
+    if resource.update_with_password(params[resource_name])
+      set_flash_message :notice, :updated if is_navigational_format?
+      sign_in resource_name, resource, :bypass => true
+      render json: {success:true, msg: "Password successfully update!"}.to_json
+    else
+      clean_up_passwords(resource)
+      error_msg = resource.errors.full_messages.join("<br />")
+      render :json => {success: false, msg: error_msg}.to_json
+    end
+  end
+end