Stick to Go's terminology.

It seems better.

git_buf_set/git_buf_sets uses other algorithm, so it is not the same as
bwrite/bwritestr.

Lets follow Go's naming so.

Signed-off-by: Thiago Farina <tfarina@chromium.org>
Rename users.sql to sqlite-schema.sql

Signed-off-by: Thiago Farina <tfarina@chromium.org>