Update readme with parameters and example

README.md

@@ -1,4 +1,51 @@
 # Rocket.Chat notifications GitHub action
 
-This is my first action so I'll experiment here.
-I'll write nice docs once I have at least a POC.
+This action will write a message on your rocket.chat server using credentials instead of a webhook.
+
+## Inputs
+
+### `user`
+
+**Required** The username to login to your rocket.chat server.
+
+### `password`
+
+**Required** The password to login to your rocket.chat server.
+
+### `message`
+
+**Required** The message you want to send.
+
+### `server`
+
+Your rocket.chat server. Default `"https://open.rocket.chat"`.
+
+### `channel`
+
+The channel you want to write to. Default `"GENERAL"`.
+
+### `code`
+
+Set it to true if you wish to have a code block. Default `"false"`.
+
+## Example usage
+
+```yaml
+on: [push]
+
+jobs:
+  rocketchat_job:
+    runs-on: ubuntu-latest
+    name: Push notification to rocket.chat
+    steps:
+    - name: Push notification to rocket.chat if the job failed
+      id: error-notification
+      if: ${{ failure() }}
+      uses: jadolg/rocketchat-notification-action@1.0.0
+      with:
+        server: ${{ secrets.ROCKETCHAT_SERVER }}
+        message: Wooops! Looks like something went wrong!
+        user: ${{ secrets.ROCKETCHAT_USER }}
+        password: ${{ secrets.ROCKETCHAT_PASSWORD }}
+        channel: alerts
+```