Create a template with thor

app.tt

<%= name %>
<%= config[:username] %>
<%= config[:domain] %>

Thorfile

require 'thor'

class Generator < Thor::Group
  include Thor::Actions

  argument :name

  class_option :username, aliases: '-u', required: true
  class_option :domain, aliases: '-d'

  def self.source_root
    File.dirname(__FILE__)
  end

  def create_lib_file
    say "project_name: #{name}", :green
    say "username: #{options[:username]}", :green

    if options[:domain]
      say "domain: #{options[:domain]}", :green
    else
      say "Please set up domain later.", :red
    end

    config = {
      username: options[:username],
      domain: options[:domain]
    }

    template('templates/projects/app.tt', "projects/#{name}/app.rb.sample", config)
  end
end