zhhz/dm-array.uniq!.rb

## dm-array.uniq!.rb
# DM 0.9.9
users = User.all
names = users.collect{|u| u.first_name}
names.uniq # works well, return all the names
names.uniq! # diff from MRI: return nil

# MRI
a = [1, 2, 3, 1, 2]
a.uniq #[3]
puts a #[1, 2, 3, 1, 2]
a.uniq! #[3] # diff from the DM
puts a # [3]
	# DM 0.9.9
	users = User.all
	names = users.collect{\|u\| u.first_name}
	names.uniq # works well, return all the names
	names.uniq! # diff from MRI: return nil

	# MRI
	a = [1, 2, 3, 1, 2]
	a.uniq #[3]
	puts a #[1, 2, 3, 1, 2]
	a.uniq! #[3] # diff from the DM
	puts a # [3]