The generator matrix

 1  0  0  1  1  1  1  1 5X  1  1  1  1  1  1  1  1  1  1  1
 0  1  0 5X+1  3 5X+2 5X 5X+3  1  6  1 4X+2 5X+6  4  5 4X 4X+1 X+3 2X+2 2X+6
 0  0  1 5X+5  3 5X+6 5X+1 5X+4 5X+2 X+3 X+2  X 4X+4  2 3X+5 4X+2 X+6 6X+5 3X+3 X+1

generates a code of length 20 over Z7[X]/(X^2) who´s minimum homogenous weight is 108.

Homogenous weight enumerator: w(x)=1x^0+168x^108+3276x^109+4536x^110+108x^112+588x^114+2016x^115+16380x^116+12096x^117+156x^119+14406x^120+3528x^121+6048x^122+33852x^123+20412x^124+24x^126+12x^133+42x^140

The gray image is a linear code over GF(7) with n=140, k=6 and d=108.
This code was found by Heurico 1.16 in 1.05 seconds.