Add an extension for connecting Review Board to Sentry.io.

Review Request #10292 — Created Oct. 30, 2018 and submitted — Latest diff uploaded

Information

rb-extension-pack
master
bb03798...

Reviewers

This extension makes it easy to catch errors from both the front- and
back-end and report them to a project on Sentry.io.

Connected my devserver and caused some errors to occur. Saw issues pop
up correctly.