Docker role basic doc

ansible/playbooks/roles/docker/README.md

@@ -1,12 +1,14 @@
-Role Name
+Docker Role
 =========
 
-A brief description of the role goes here.
+Tasks : 
+- Installs dependencies and docker env [tasks/install.yml](tasks/install.yml)
+- Creates user docker (group docker) for docker operations [tasks/docker_user.yml](tasks/docker_user.yml)
 
 Requirements
 ------------
 
-Any pre-requisites that may not be covered by Ansible itself or the role should be mentioned here. For instance, if the role uses the EC2 module, it may be a good idea to mention in this section that the boto package is required.
+Uses **become**
 
 Role Variables
 --------------