username column added to users table
modified devise.rb, changed :email to :username in 3 config settings
generate devise:views
added :username instead of :email in #app/views/devise/sessions/new.html.erb
for signup-added :username field in #app/views/devise/registration/new.html.erb and in user model- attr_accessible :username (different approach for rails 4)
sign in with username or email