[app-name] in docker-app push is not optional.

[Dimrok]

$ ls -l
-rw-r--r-- 1 dimrok dimrok 1786 mai   22 14:26 docker-compose.yml
-rw-r--r-- 1 dimrok dimrok  167 mai   22 10:42 metadata.yml
-rw-r--r-- 1 dimrok dimrok  437 mai   22 14:27 settings.yml
$ docker-app push -p dimrok/ -t latest
Error: error from docker push command: invalid reference format
: exit status 1
$ cd ..
$ ls -l
drwxr-xr-x 5 dimrok dimrok 4096 mai   22 15:58 voting-app.dockerapp
$ docker-app push -p dimrok/ -t latest
Error: error from docker push command: invalid reference format
: exit status 1
$ docker-app push -p dimrok/ -t latest voting-app.dockerapp
✔

[mnottale]

Fixed.