Updating the documentatioon

README.md

@@ -56,6 +56,9 @@ So in order to upgrade Docker on managed systems, take the following steps:
    host/group vars.
 1. Run your playbook with `-e upgrade_docker=True`
 
+### `docker_proxy`, `docker_http_proxy`, `docker_https_proxy`, `docker_no_proxy`
+
+Specify if proxy settings. docker_proxy specifies if proxy need to be applied. Default value of `docker_proxy` is no. If you need proxy set it to yes and updated other three variables as needed.
 
 Dependencies
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