Update configuration of one or more containers

Docker update dynamically updates docker configurations.

Eg:

CPU Shares before update:
[root@localhost /]# docker inspect edd512ee70b7
[
.
.
.
.
"CpuShares": 512,
"Memory": 0,
Docker update performed on container edd512ee70b7

[root@localhost /]# docker update --cpu-shares 256 edd512ee70b7
edd512ee70b7
CPU shares after update:
[root@localhost /]# docker inspect edd512ee70b7
"Dns": [],
"DnsOptions": [],
"DnsSearch": [],
"ExtraHosts": null,
"GroupAdd": null,
"IpcMode": "private",
"Cgroup": "",
"Links": null,
"OomScoreAdj": 0,
"PidMode": "",
"Privileged": false,
"PublishAllPorts": false,
"ReadonlyRootfs": false,
"SecurityOpt": null,
"UTSMode": "",
"UsernsMode": "",
"ShmSize": 67108864,
"Runtime": "runc",
"ConsoleSize": [
0,
0
],
"Isolation": "",
"CpuShares": 256,