Add usage section to README

Change-Id: Id29ea00af667dac18e41014fb9e72e8816a5f9a1

README.rst

@@ -4,6 +4,44 @@ rally-openstack
 
 Rally plugins for `OpenStack platform <https://openstack.org>`_
 
+
+Usage
+-----
+
+..code-block:: bash
+
+    # Install this package (will install rally if not installed)
+    pip install rally-openstack
+
+    # List all installed plugins
+    rally plugin --platform openstack
+
+    # Create OpenStack Env
+
+    cat <<EOT >> env.yaml
+    ---
+    openstack:
+      auth_url: "https://keystone.net/identity"
+      region_name: RegionOne
+      https_insecure: False
+      users:
+        - username: user_that_runs_commands
+          password: his password
+          project_name: project_that_users_belong_to
+    EOT
+
+    rally env create --name my_openstack --spec env.yml
+
+    # Check that you provide correct credentials
+    rally env check
+
+    # Collect key Open Stack metrics
+    rally task start ./tasks/openstack_metrics/task.yaml --task-args {"image_name": "image_to_use", "flavor_name": "flavor_to_use"}
+
+    # Generate Repot
+    rally task report --out report.html
+
+
 Links
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