docs: Add readme

Author: Ehesp

README.md

@@ -1,3 +1,53 @@
 # firebase-emulator-action
 
-An action which starts the Firebase Emulator Suite.
+An action which starts the Firebase Emulator Suite.
+
+## Usage
+
+Prerequisites for this action:
+
+- Node.js
+- Java
+
+To use the action, use the `firebase-emulator-action` action:
+
+```yaml
+steps:
+  # Ensure Node.js is installed (See https://github.com/actions/setup-node)
+  - name: Setup Node.js
+    uses: actions/setup-node@v4
+    with:
+      node-version: 20
+
+  # Ensure Java is installed (See https://github.com/actions/setup-java)
+  - name: Setup Java
+    uses: actions/setup-java@v4
+    with:
+      distribution: 'temurin'
+      java-version: '17'
+  
+  # Install the Firebase Emulator Suite
+  - name: Start Firebase Emulator Suite
+    uses: firebase-emulator-action@v1
+    with:
+      # The version of the Firebase CLI to install, (`npm install -g firebase-tools@${firebase-tools-version}`)
+      firebase-tools-version: 'latest'
+
+      # A comma separated list of emulators to start.
+      emulators: 'auth,firestore,functions,storage,database'
+
+      # The project ID to use, defaults to 'test-project'.
+      project-id: 'test-project'
+
+      # The maximum number of retries to attempt before failing the action, defaults to 3.
+      max-retries: '3'
+
+      # The maximum number of checks to perform before failing the retry, defaults to 60.
+      max-checks: '60'
+
+      # The time to wait between checks in seconds, defaults to 1.
+      wait-time: '1'
+
+      # The port to check for the emulators, defaults to 9099 (Cloud Firestore). Change this if you are using specific emulators. See https://firebase.google.com/docs/emulator-suite/install_and_configure#port_configuration.
+      check-port: '9099'
+```