Official documentation here
!!! warning This installation is suitable only for developpement, not for production. See here
docker run -d --restart=always --name wekan-db mongo:3.2.21
docker run -d --restart=always --name wekan --link "wekan-db:db" -e "MONGO_URL=mongodb://db" -e "ROOT_URL=http://localhost:8080" -p 8080:8080 quay.io/wekan/wekan
So now, you can access to wekan at http://localhost:8080/