Declare `NotesController`

This commit responds to the previous error:

Error:
UserSharesAMessagesTest#test_visiting_the_index:
ActionController::RoutingError: uninitialized constant NotesController
Did you mean?  ActionController

To resolve that error, declare a NotesController class in the app/controllers directory.

When we execute our test suite, a new error is raised:

Error:
UserSharesAMessageTest#test_visiting_the_index:
DRb::DRbRemoteError: undefined method `make_response!' for NotesController:Class (NoMethodError)


      app/controllers/notes_controller.rb

diff --git a/app/controllers/notes_controller.rb b/app/controllers/notes_controller.rb
new file mode 100644
index 0000000..bb3ba93
--- /dev/null
+++ b/app/controllers/notes_controller.rb
@@ -0,0 +1,2 @@
+class NotesController
+end

Declare NotesController

Declare `NotesController`