gitea: migration from version 1.8.3 to version 1.9.0 fails

• Gitea version (or commit ref): 1.9.0
• Operating system: linux / docker
• Database (use [x]):
  • PostgreSQL
  • MySQL
  • MSSQL
  • SQLite
• Can you reproduce the bug at https://try.gitea.io:
  • Yes (provide example URL)
  • No
  • Not relevant
• Log gist:

Description

I have a running 1.8.3 gitea docker server. All works fine. Now I wanted to upgrade to the new version 1.9.0. The server seems to be in a neverending loop initializing itself. All I see in my docker logs is repeatingly endless.

gitea_server_1  | 2019/08/01 05:59:58 ...dules/setting/git.go:83:newGit() [I] Git Version: 2.22.0, Wire Protocol Version 2 Enabled
gitea_server_1  | 2019/08/01 05:59:58 routers/init.go:72:GlobalInit() [T] AppPath: /app/gitea/gitea
gitea_server_1  | 2019/08/01 05:59:58 routers/init.go:73:GlobalInit() [T] AppWorkPath: /app/gitea
gitea_server_1  | 2019/08/01 05:59:58 routers/init.go:74:GlobalInit() [T] Custom path: /data/gitea
gitea_server_1  | 2019/08/01 05:59:58 routers/init.go:75:GlobalInit() [T] Log path: /data/gitea/log
gitea_server_1  | 2019/08/01 05:59:58 ...dules/setting/log.go:226:newLogService() [I] Gitea v1.9.0 built with GNU Make 4.2.1, go1.12.7 : bindata, sqlite, sqlite_unlock_notify

Where should I look for additional informations? Logs?