jasonyb

Hi @LuminaScript. You are free to submit a PR at any time. You can add test coverage in `src/postgres/src/test/regress/*/yb_tablegroup.*`, perhaps add new files.

Currently, `amroutine->amcanmulticol = false`. This means that gin indexes can only index a single column, not multiple columns. There's also `amroutine->amcaninclude = false`, but that is a limitation with upstream...