refactor: remove pool dependency
refactor: remove pool dependency

nbushak/postgraphql,ferdinandsalis/postgraphql,nbushak/postgraphql,postgraphql/postgraphql,ferdinandsalis/postgraphql,postgraphql/postgraphql,calebmer/postgraphql,calebmer/postgraphql,postgraphql/postgraphql,calebmer/postgraphql,nbushak/postgraphql,postgraphql/postgraphql,nbushak/postgraphql,calebmer/postgraphql