bootstrap/css added - add sections table - add foreign key for sections to lessons
section has many lessons and verifies presence of name
lesson belongs to section validation and test
add route for section index
add index to controller and index.html.erb
index page lists all Sections, error checking and form entry for new sections
fix bug on index with name missing error message
add show method and view for sections class
add edit/update methods to Sections class
delete added
refactored errors / forms into partials
add default scope for order