The git-ignored target directory for LMS Sass compilation is:
lms/static/css
Unfortunately, that directory contains git-controlled directory of
vendored-in static assets:
lms/static/css/vendor
This is a problem for a couple reasons:
1. In Tutor, we would like to make lms/static/css a symlink to an
external location for the sake of build efficiency. This is
impossible to do without clobbering lms/static/css/vendor and
dirtying the git state.
2. More generally, when optimizing (or just understanding) a build
system, it adds complexity when git-controlled source directories are
mixed up inside git-ignored target directories.
The solution is to simply merge these vendored-in assets to another
existing git-controlled vendor directory:
common/static/css/vendor
LMS already reads assets from this folder, so no further changes need to
be made. common/static/css is fully git-controlled, so we avoid the
complexity described above.