Time in Words - Ruby Helper

Time in Words - Ruby Helper

def time_ago_in_words(timestamp)
    minutes = (((Time.now - timestamp).abs)/60).round
    return nil if minutes < 0
    case
        when minutes < 1    then "less than a minute ago"
        when minutes == 1   then "1 minute ago"
        when minutes < 50   then "#{minutes} minutes ago"
        when minutes < 90   then "1 hour ago"
        when minutes < 1440 then "#{(minutes / 60).round} hours ago"
    else 
        timestamp.strftime('%d %b %Y')
    end
end