refactor static page test with shared_examples
fix typo in home page
add test of links
add User model
db migrate
add annotate to Gemfile
add annotate to model
add user model test
add test for user attr validation
add validation for name and email
add test for too long user name
add validation for email and name. the length of name must be smaller then 50.  email must fit format. email must unique
validate email uniqueness
user's email must be unique, not case sensitive
update test to validete email umiquness
add index to users email for db. check email uniqueness
migrate db with add_index_to_users_email
downcase users email before save.
add bcrypt gem
add test to check user have password_digest