The generator matrix

 1  0  0  0  0  0  0  1  1  1  0  1  1  X  0
 0  1  0  0  0  0  0  0  0  0  1  X X+1  1  X
 0  0  1  0  0  0  0  0  1  0  X  X  1  1  0
 0  0  0  1  0  0  0  0  1  1  1  1  X  0  1
 0  0  0  0  1  0  0  0  1  X  X  1 X+1  X  0
 0  0  0  0  0  1  0  1  0 X+1  1  0  1  1  X
 0  0  0  0  0  0  1  1 X+1  X  1  X  1 X+1  X
 0  0  0  0  0  0  0  X  X  0  X  0  0  0  X

generates a code of length 15 over Z2[X]/(X^2) who´s minimum homogenous weight is 8.

Homogenous weight enumerator: w(x)=1x^0+492x^8+1712x^10+5165x^12+9104x^14+8833x^16+5200x^18+1858x^20+368x^22+34x^24+1x^28

The gray image is a linear code over GF(2) with n=30, k=15 and d=8.
As d=8 is an upper bound for linear (30,15,2)-codes, this code is optimal over Z2[X]/(X^2) for dimension 15.
This code was found by Heurico 1.11 in 358 seconds.