Sample thor task to create custom generators

Gemfile.tt

source 'https://rubygems.org'

# Specify your gem's dependencies in <%= gem_name %>.gemspec
gemspec

LICENSE.md

Copyright (c) 2013 MIT License Permission is hereby granted, free of charge, to any person...

newgem.thor

#!/usr/bin/env ruby
require 'thor'

class Newgem < Thor::Group
  include Thor::Actions

  # Define arguments and options
  argument :gem_name
  class_option :test_framework, :default => :test_unit

  def self.source_root
    File.dirname(__FILE__)
  end

  def create_gemfile_file
    template('Gemfile.tt', "#{gem_name}/Gemfile")
  end

  def create_test_file
    test = options[:test_framework].to_s == "rspec" ? :spec : :test
    create_file "#{gem_name}/#{test}/#{gem_name}_#{test}.rb"
  end

  def copy_licence
    copy_file "LICENSE.md", "#{gem_name}/LICENSE.md"
  end
end
                                                                                                         

newgem.thor.run.rb

#!/usr/bin/env ruby
require_relative 'newgem.thor'

# From the command-line you would invoke this task like this:
# $ thor newgem some_name --test-framework rspec
#
# This is how ARGV would look like after that invocation:
# ["newgem", "some_name", "--test-framework", "rspec"]
#
# This is how you should pass the arguments directly to your script
#
#  If you use start() pass options like this:
#    args = ["some_name", "--test-framework", "rspec"]
#
#    Newgem.start(args)
#
#
#  If you use invoke() pass options like this:
#    args = ["some_name"]
#    opts = {:test_framework => 'rspec'}
#
#    script = Newgem.new(args, opts)
#    script.invoke_all
#
#  Using invoke() is the suggested technique.

args = ["some_name"]
opts = {:test_framework => 'rspec'}

script = Newgem.new(args, opts)
script.invoke_all

Ref: https://github.com/wycats/thor/wiki/Generators