This is a very quick install for SonarQube on Ubuntu 18.04 LTS. I presume you got the latest Docker CE 18.09 and docker-compose 1.24 installed.

# create folders for sonarqube files and postgres
sudo mkdir -p /var/sonarqube/{conf,data,logs,extensions}
sudo chown -R 999:999 /var/sonarqube
sudo mkdir -p /var/sonarqube/postgres
# make folder for all Docker files in home
mkdir ~/sonarqube
cd sonarqube
# create docker-compose.yml with following content
version: '3.1'
services:
  db:
    image: postgres:9.6-alpine
    restart: unless-stopped
    volumes:
      - /var/sonarqube/postgres:/var/lib/postgresql/data
    environment:
     - POSTGRES_USER=sonar
     - POSTGRES_PASSWORD=sonar

  sonarqube:
    image: sonarqube:6.7-community
    ports:
      - 9000:9000
      - 9092:9092
    restart: unless-stopped
    volumes:
      - /var/sonarqube/conf:/opt/sonarqube/conf
      - /var/sonarqube/data:/opt/sonarqube/data
      - /var/sonarqube/logs:/opt/sonarqube/logs
      - /var/sonarqube/extensions:/opt/sonarqube/extensions
    environment:
      - SONARQUBE_HOME=/opt/sonarqube
      - SONARQUBE_JDBC_USERNAME=sonar
      - SONARQUBE_JDBC_PASSWORD=sonar
      - SONARQUBE_JDBC_URL=jdbc:postgresql://db/sonar
# launch 
docker-compose up -d

You can then access your SonarQube instance on http://<ServerIP>:9000 with the credential admin/admin.