gistfile1.builder

# config/environment.rb
# setting default timezone for your app when firing up Rails
config.time_zone = 'UTC'

# app/controllers/application_controller.rb
# changing timezone to one selected by user if logged in
before_filter :set_time_zone
def set_time_zone
  Time.zone = current_user.time_zone if logged_in?
end

# bunch of useful methods in http://apidock.com/rails/DateTime
# http://apidock.com/rails/DateTime/in_time_zone
# http://apidock.com/rails/DateTime/utc