renamed starred_by_did column to did
remove foreign key constraints from repo_at column to support
targetting non-ingested repository or sh.tangled.string. the column
isn't renamed yet because I'm afraid to break somewhere with that
rename. We really need some test code here.
Signed-off-by: Seongmin Lee git@boltless.me
bit confusing that the
repo_atcol of the stars table can now refer to anything. can we rename that column too? to something more generic liketarget?