Add Firefox and Chromium to contribution guidelines
Add Firefox and Chromium to contribution guidelines
gdh1995/vimium,decaffeinate-examples/vimium,poacher2k/vimium,gdh1995/vimium,smblott-github/vimium,smblott-github/vimium,poacher2k/vimium,philc/vimium,philc/vimium,philc/vimium,mrmr1993/vimium,poacher2k/vimium,mrmr1993/vimium,decaffeinate-examples/vimium,decaffeinate-examples/vimium,smblott-github/vimium,mrmr1993/vimium,gdh1995/vimium