How much time has passed

time_ago.rb

def prettyDate(created_at)
    now = Time.now.to_i
    before = Time.parse(created_at).to_i
    diff = now - before

    minute = 60
    hour = 60 * minute
    day = 24 * hour
    week = 7 * day
    year = 365 * day

    years_past = diff / year
    weeks_past = diff / week
    hours_past = diff / hour
    days_past = diff / day
    minutes_past = diff / minute
    seconds_past = diff

    if years_past > 0
      return "#{years_past}y"
    elsif weeks_past > 0
      return "#{weeks_past}w"
    elsif days_past > 0
      return "#{days_past}d"
    elsif hours_past > 0
      return "#{hours_past}h"
    elsif minutes_past > 0
      return "#{minutes_past}m"
    else
      return "#{seconds_past}s"
    end
  end