Make uniqueness of user name case insensitive, shorten spec with shoulda
Make uniqueness of project name case insensitive
Implement in-place editing of person description

* update feature spec editing_a_person_spec
* add column 'description' to users
* update view 'presenters/person_presenter/_person.html.haml'
* setup route 'people#update'
* setup controller action 'people#update'