How can I remove Teams from Gitlab Mattermost

I found that platform command is available as 'mattermost' in GitLab integrated version but the use of a command gives an error:

/opt/gitlab/embedded/bin/mattermost -permanent_delete_team -team_name="test2" -email="myemai@domain.org" panic: Error opening config file=config.json, err=open config.json: no such file or directory
goroutine 1 [running]:
github.com/mattermost/platform/utils.LoadConfig(0xc26f50, 0xb)
/go/src/github.com/mattermost/platform/utils/config.go:139 +0x16a
main.main()
/go/src/github.com/mattermost/platform/mattermost.go:54 +0x43
goroutine 17 [syscall, locked to thread]:
runtime.goexit()
/usr/local/go/src/runtime/asm_amd64.s:1696 +0x1
goroutine 20 [syscall]:
os/signal.loop()
/usr/local/go/src/os/signal/signal_unix.go:22 +0x18
   created by os/signal.init.1
/usr/local/go/src/os/signal/signal_unix.go:28 +0x37
goroutine 21 [chan receive]:
  code.google.com/p/log4go.ConsoleLogWriter.run(0xc820060120, 0x7f73b35911c0, 0xc82006c008)
    /go/src/github.com/mattermost/platform/Godeps/_workspace/src/code.google.com/p/log4go/termlog.go:27 +0x80
created by code.google.com/p/log4go.NewConsoleLogWriter
    /go/src/github.com/mattermost/platform/Godeps/_workspace/src/code.google.com/p/log4go/termlog.go:19 +0x6e

Any suggestions how should it be used?

K.