catch conflict errors
Closes https://gitlab.coko.foundation/pubsweet/pubsweet-server/issues/61
Validation errors now return bad request instead of 500
rev
is a required property on PATCHes
Edited by Sam Galson
Closes https://gitlab.coko.foundation/pubsweet/pubsweet-server/issues/61
Validation errors now return bad request instead of 500
rev
is a required property on PATCHes