Created all infrastructure to handle basic pledges on product#show

for pledges_controller.rb Line 8, should we use @pledge.backer_id = current_user.id instead? Does this make a difference?

for pledges_controller.rb Line 13, should we use @pledge.project or @pledge.project_id? 

for the projects_controller.rb Line 47, should there be permitting the :_destroy action? This permit field should be for things that the user inputs right?