add column role to users table
change a role name in the ability.rb
add a unique index on the name attribute of the user model
add validations for attribute name to user model
add array constant with role names to user model and set role to "Commentator" after create without role value
generate like model and establish relationships with comment, post and user models
update TODO list
add name field to signup form
create user_route.js
create users_route.js
add user routes to router.js
add show user route to routes.rb
correct link in partial _header
adapt and extend posts.feature
create new post template (unfinished)
copy posts new route and posts new controller from example (not fully adapted yet)