Adding documentation for '--cgroup-parent' option.

Docker-DCO-1.1-Signed-off-by: Vishnu Kannan <vishnuk@google.com> (github: vishh)

docs/man/docker-create.1.md

@@ -46,6 +46,7 @@ docker-create - Create a new container
 [**-v**|**--volume**[=*[]*]]
 [**--volumes-from**[=*[]*]]
 [**-w**|**--workdir**[=*WORKDIR*]]
+[**--cgroup-parent**[=*CGROUP-PATH*]]
 IMAGE [COMMAND] [ARG...]
 
 # OPTIONS
@@ -67,6 +68,9 @@ IMAGE [COMMAND] [ARG...]
 **--cidfile**=""
    Write the container ID to the file
 
+**--cgroup-parent**=""
+   Path to cgroups under which the cgroup for the container will be created. If the path is not absolute, the path is considered to be relative to the cgroups path of the init process. Cgroups will be created if they do not already exist.
+
 **--cpuset-cpus**=""
    CPUs in which to allow execution (0-3, 0,1)
 

docs/man/docker-run.1.md

@@ -49,6 +49,7 @@ docker-run - Run a command in a new container
 [**-v**|**--volume**[=*[]*]]
 [**--volumes-from**[=*[]*]]
 [**-w**|**--workdir**[=*WORKDIR*]]
+[**--cgroup-parent**[=*CGROUP-PATH*]]
 IMAGE [COMMAND] [ARG...]
 
 # DESCRIPTION
@@ -124,6 +125,9 @@ division of CPU shares:
 **--cap-drop**=[]
    Drop Linux capabilities
 
+**--cgroup-parent**=""
+   Path to cgroups under which the cgroup for the container will be created. If the path is not absolute, the path is considered to be relative to the cgroups path of the init process. Cgroups will be created if they do not already exist.
+
 **--cidfile**=""
    Write the container ID to the file
 

docs/sources/reference/commandline/cli.md

@@ -805,6 +805,7 @@ Creates a new container.
       -c, --cpu-shares=0         CPU shares (relative weight)
       --cap-add=[]               Add Linux capabilities
       --cap-drop=[]              Drop Linux capabilities
+      --cgroup-parent=           Optional parent cgroup for the container
       --cidfile=""               Write the container ID to the file
       --cpuset-cpus=""           CPUs in which to allow execution (0-3, 0,1)
       --device=[]                Add a host device to the container