fix lesson factory to include nested project with same user_id

Author: Scott Adams

spec/factories/lesson.rb

@@ -6,6 +6,6 @@
     sequence(:name) { |n| "Lesson #{n}" }
     description { 'Description' }
     visibility { 'teachers' }
-    project { create(:project) }
+    project { create(:project, user_id: user_id) }
   end
 end