Minor edits to form for adding a new lesson
Passing :lessons instead of :lesson

The local variable passed has to match what :type key in
the RABL ( rendered by course/lessons ). And we have decided
to go with the plural form
Singular of freebies is freebie - not freeby ( as Rails default infers )
Added ability to create a new lesson as a standalone asset

Once created, a lesson can then be attached or detached from a
course the same way quizzes are