class Array

[ [ 0, 1 ] ].including([ [ 1, 0 ] ]) # => [ [ 0, 1 ], [ 1, 0 ] ]
[ 1, 2, 3 ].including(4, 5) # => [ 1, 2, 3, 4, 5 ]

Returns a new array that includes the passed elements.

def including(*elements)
  self + elements.flatten(1)
end