Error upgrade from 0.5 to 0.8

Hi I’m in the process of upgrading our drone server from 0.5 to version 0.8.
We’re running drone in Kubernetes and using helm to deploy stuffs.

It seems there’s an issue with database migration. Here is the log:

time="2017-10-10T12:26:28Z" level=info ip=125.234.115.178 latency=1.830412ms method=GET path="/api/repos/honestbee/helm-charts/builds" status=404 time="2017-10-10T12:26:28Z" user-agent="Mozilla/5.0 (Macintosh; Intel Mac OS X 10_13_0) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/61.0.3163.100 Safari/537.36"
time="2017-10-10T12:26:31Z" level=error msg="failure to find repo honestbee/helm-charts from hook. sql: Scan error on column index 18: unsupported Scan, storing driver.Value type <nil> into type *string"
time="2017-10-10T12:26:31Z" level=error msg="Error #01: sql: Scan error on column index 18: unsupported Scan, storing driver.Value type <nil> into type *string\n" ip=192.30.252.42 latency=2.48658ms method=POST path="/hook" status=404 time="2017-10-10T12:26:31Z" user-agent="GitHub-Hookshot/0e7adb7"
time="2017-10-10T12:26:32Z" level=error msg="failure to find repo honestbee/helm-charts from hook. sql: Scan error on column index 18: unsupported Scan, storing driver.Value type <nil> into type *string"
time="2017-10-10T12:26:32Z" level=error msg="Error #01: sql: Scan error on column index 18: unsupported Scan, storing driver.Value type <nil> into type *string\n" ip=192.30.252.41 latency=3.029481ms method=POST path="/hook" status=404 time="2017-10-10T12:26:32Z" user-agent="GitHub-Hookshot/0e7adb7"

As it showed, we’re unable to browse the build history, not sure why…

Any idea? Thanks!