introduce devise
add user first and last names
add sign up/in/out
Merge branch 'feature/auth_devise' into develop
add user_id to job_posts
display author info
introduce simple_form gem
modify navigation links
updated fronted for the new authentication system

Added simple_form
Updated several forms for Bootstrap/simple_form
Added login/logout/register links to nav
Add a collection select to job_post form
Merge branch 'feature/users_posts_relations' into develop