Fix current user removal

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

app/controllers/registrations_controller.rb

@@ -6,7 +6,7 @@ class RegistrationsController < Devise::RegistrationsController
   end
 
   def destroy
-    DeleteUserService.new.execute(user)
+    DeleteUserService.new.execute(current_user)
 
     respond_to do |format|
       format.html { redirect_to new_user_session_path, notice: "Account successfully removed." }