docker pages: add homepages

pages/common/docker-compose.md

@@ -1,6 +1,7 @@
 # docker-compose
 
 > Run and manage multi container docker applications.
+> Homepage: <https://docs.docker.com/compose/reference/overview/>.
 
 - Create and start all containers in the background using a `docker-compose.yml` file from the current directory:
 

pages/common/docker-machine.md

@@ -1,6 +1,7 @@
 # docker-machine
 
 > Create and manage machines running Docker.
+> Homepage: <https://docs.docker.com/machine/reference/>.
 
 - List currently running docker machines:
 

pages/common/docker.md

@@ -1,6 +1,7 @@
 # docker
 
 > Manage Docker containers and images.
+> Homepage: <https://docs.docker.com/engine/reference/commandline/cli/>.
 
 - List currently running docker containers: