Add mounts to docker ps.

- Allow to filter containers by volume with `--filter volume=name` and `filter volume=/dest`.
- Show their names in the list with the custom format `{{ .Mounts }}`.

Signed-off-by: David Calavera <david.calavera@gmail.com>

man/docker-ps.1.md

@@ -35,6 +35,7 @@ the running containers.
    - before=(<container-name>|<container-id>)
    - since=(<container-name>|<container-id>)
    - ancestor=(<image-name>[:tag]|<image-id>|<image@digest>) - containers created from an image or a descendant.
+   - volume=(<volume-name>|<mount-point-destination>)
 
 **--format**="*TEMPLATE*"
    Pretty-print containers using a Go template.
@@ -50,6 +51,7 @@ the running containers.
       .Names - Container names.
       .Labels - All labels assigned to the container.
       .Label - Value of a specific label for this container. For example `{{.Label "com.docker.swarm.cpu"}}`
+      .Mounts - Names of the volumes mounted in this container.
 
 **--help**
   Print usage statement
@@ -118,6 +120,18 @@ the running containers.
     c1d3b0166030        debian
     41d50ecd2f57        fedora
 
+# Display containers with `remote-volume` mounted
+
+    $ docker ps --filter volume=remote-volume --format "table {{.ID}}\t{{.Mounts}}"
+    CONTAINER ID        MOUNTS
+    9c3527ed70ce        remote-volume
+
+# Display containers with a volume mounted in `/data`
+
+    $ docker ps --filter volume=/data --format "table {{.ID}}\t{{.Mounts}}"
+    CONTAINER ID        MOUNTS
+    9c3527ed70ce        remote-volume
+
 # HISTORY
 April 2014, Originally compiled by William Henry (whenry at redhat dot com)
 based on docker.com source material and internal work.