Run the following commands as root:
Make sure docker daemon is running:

zypper in docker docker-compose
systemctl enable docker
systemctl start docker

Clone the repository and start the docker-compose file:

git clone https://github.com/FrankFlorian/hordeOnLeap15.0.git
docker-compose -f docker-compose.yml up
docker exec -it hordeonleap150_db_1 mysql -p -e "create database horde; grant all on horde.* to 'horde'@'%' identified by 'horde'";

-> Password: horde

Use the frontend(localhost) for building the new configuration: Go to the gear symbol select Administration->Configuration and then select the configuration for Horde(Horde (horde) 6.0.0-git).

Stay at the "General"-tab and scroll down to Session Settings:

$conf[cookie][domain] = ""

Go to the "Database"-tab and fill in the following valus:

$conf['sql']['phptype'] = MySQL/PDO
$conf['sql']['username'] = horde
$conf['sql']['password'] = horde
$conf['sql']['protocol'] = TCP/IP
$conf['sql']['hostspec'] = hordeonleap150_db_1
$conf['sql']['port'] = 3306
$conf['sql']['database'] = horde
$conf['sql']['charset'] = utf-8
$conf['sql']['ssl'] = No
$conf['sql']['splitread'] = Disabled
$conf['sql']['logqueries'] = no checkmark

docker exec -it hordeonleap150_php_1 /srv/git/horde/base/bin/horde-db-migrate