Example Rails 5 application using devise_invitable

App design

User belongs to Account Account has_many users

Steps I took

Add gems

gem 'devise'
gem 'simple_form'
gem 'devise_invitable'

Bundle and install gems

bundle
rails g simple_form:install
rails g devise:install
rails g devise User
rails g devise_invitable:install
rails g devise_invitable User
rails db:migrate

Create home page

rails g controller home index

Set home page to root in /config/routes.rb

root 'home#index'

Add account_id field to User model by creating a migration

rails g migration AddAccountIdToUser account_id:references

Add the account scaffold

rails g scaffold Account name account_type
rails db:migrate

Add a field to the top of the new account form to capture the account owner email

<%= f.input :owner_email %>

Add to /models/account.rb to allow this virtual attribute

attr_accessor :owner_email
has_many :users

Add owner_email to account_params method in /app/controllers/accounts_controller.rb

def account_params
  params.require(:account).permit(:name, :account_type, :active, :owner_email)
end