[READ-ONLY] Mirror of https://github.com/mostlyobvious/En57. DCB-compatible event store library in Ruby with support for PostgreSQL.

Return append position master

- Include the last appended event position in successful append results so callers can continue from the write boundary without issuing a read. - Return the position from the SQL append result alongside the status to keep the Ruby result derived from the database write. - Preserve nil for successful empty appends because no event position is created in that case.