class Log < ActiveRecord::Base
	def self.calculate_time(log)
    @result = Time.at(log.updated_at - log.created_at).gmtime.strftime('%R:%S')
  end

  def self.calculate_all_time(username)
  	@log = Log.find_all_by_username(username)
  	seconds = 0
  	@log.each do |f|
  		seconds += (f.updated_at - f.created_at)
  	end
  	Time.at(seconds).gmtime.strftime('%R:%S')
  end
end