'rails g controller welcome index'

We need some sort of default welcome/home/index page for the user. So,
this is a bare minimum, 1-page controller.
make welcome#index the site root

We also remove `get 'welcome/index'` to invalidate requests to the
address "/welcome/index", as that is redundant.
welcome#index: describe what 'FIDO' is
'rails g scaffold User name:string password:digest'
use bcrypt gem
User: some basic validations

A user must have a non-zero-length 'name' attribute, and it must also be
unique amongst all of the existing users in the database.

We also update the tests to pass the uniqueness validation.
add db schema
/users: sort users by name
.gitignore: add 'vendor' folder
add feature doc
user: add basic validations
'rails g model Role description:integer'
.gitignore: ignore feature doc html export
add Gemfile.lock
'rails g model Tenant name:string admin_id:integer'
'rake db:migrate'
roles: description: change to string (varchar)