README: update

README.md

@@ -1,2 +1,18 @@
 # Run Ansible playbook Github Action
 
+An action that executes given Ansible playbook on selected hosts.
+
+## Usage
+
+```yaml
+- name: Run playbook
+  uses: dawidd6/action-ansible-playbook
+  with:
+    playbook: deploy.yml
+    key: ${{secrets.SSH_PRIVATE_KEY}}
+    options: |
+      --inventory hosts
+      --limit dev
+      --extra-vars hello=there
+      --verbose
+```