Comment 4 for bug 1396213

I've generated the report and I'm trying to use what the linked tutorial suggests:

$ ubuntu-bug -c 1396213.apport -u 1396213
Usage: ubuntu-bug [options] [symptom|pid|package|program path|.apport/.crash file]

ubuntu-bug: error: -u/--update-bug option cannot be used together with options for a new report

That tutorial must be outdate, and I couldn't figure out how the syntax changed to make it send the report and file it under this existing bug. I get the same with "apport-cli". What is the correct command to use if I have the report file, and want it to be attached here?