How to Use ActiveSupport Within Sinatra

# Gemfile
source 'https://rubygems.org'

gem 'sinatra', '1.4.5'
gem 'activesupport', '4.1.4'

# app.rb
require 'active_support/all'
require 'sinatra'

Time::DATE_FORMATS[:my_datetime] = "%Y-%m-%d Hour: %H Minute: %M Second: %S"

get '/' do
  Time.now.to_s(:my_datetime)
end