Added 24 issues to [Young GANGAN] Collection

Previews & DDL:

	[Young GANGAN] 2015 No.01
	[Young GANGAN] 2015 No.02
	[Young GANGAN] 2015 No.03
	[Young GANGAN] 2015 No.04
	[Young GANGAN] 2015 No.05
	[Young GANGAN] 2015 No.06
	[Young GANGAN] 2015 No.07
	[Young GANGAN] 2015 No.08
	[Young GANGAN] 2015 No.09
	[Young GANGAN] 2015 No.10
	[Young GANGAN] 2015 No.11
	[Young GANGAN] 2015 No.12
	[Young GANGAN] 2015 No.13
	[Young GANGAN] 2015 No.14
	[Young GANGAN] 2015 No.15
	[Young GANGAN] 2015 No.16
	[Young GANGAN] 2015 No.17
	[Young GANGAN] 2015 No.18
	[Young GANGAN] 2015 No.19
	[Young GANGAN] 2015 No.20
	[Young GANGAN] 2015 No.21
	[Young GANGAN] 2015 No.22
	[Young GANGAN] 2015 No.23
	[Young GANGAN] 2015 No.24