--- concat(other)

     other  self (˲Ū)Ϣ뤷ޤ
    self ֤ޤ

    :
        array = [1, 2]
        a     = [3, 4]
        array.concat a
        p array          # => [1, 2, 3, 4]
        p a              # => [3, 4]       # Ѥʤ

