User joined project event added

app/observers/users_project_observer.rb

@@ -1,6 +1,12 @@
 class UsersProjectObserver < ActiveRecord::Observer
   def after_create(users_project)
     Notify.project_access_granted_email(users_project.id).deliver
+
+    Event.create(
+      project_id: users_project.project.id,
+      action: Event::Joined,
+      author_id: users_project.user.id
+    )
   end
 
   def after_update(users_project)