module Enumerable

def excluding(*elements)

# => {foo: 1, baz: 3}
{foo: 1, bar: 2, baz: 3}.excluding :bar

# => ["David", "Rafael"]
["David", "Rafael", "Aaron", "Todd"].excluding %w[ Aaron Todd ]

# => ["David", "Rafael"]
["David", "Rafael", "Aaron", "Todd"].excluding "Aaron", "Todd"

Returns a copy of the enumerable excluding the specified elements. 
def excluding(*elements)
  elements.flatten!(1)
  reject { |element| elements.include?(element) }
end