Added steps to build inside Docker

README.md

@@ -19,7 +19,7 @@ A React Native mobile application for receiving push notifications.
 
 ## Prerequisites
 
-- Node.js (v14 or higher)
+- Node.js (v22)
 - Firebase account with google-services.json
 - Expo account with Firebase Admin SDK private key imported
 - Installed eas-cli
@@ -49,6 +49,35 @@ npm install
 eas build --profile release --local --platform android
 ```
 
+## Building from scratch via Docker
+
+1. Clone the repository:
+```bash
+git clone <repository-url>
+cd <project-directory>
+```
+
+2. Build the Docker image
+
+```bash
+docker build -t expo-android-builder .
+```
+
+3. Copy google-services.json to root directory and comment out google-services.json in `.gitignore` (or delete the entry)
+```bash
+sed -i '/google-services\.json/d' .gitignore
+```
+
+4. Use EAS to build
+```bash
+docker run --rm \
+  -v "$PWD":/workspace \
+  -v gradle-cache:/home/node/.gradle \
+  -e EXPO_TOKEN="$EXPO_TOKEN" \
+  expo-android-builder \
+  bash -c 'npm ci && eas build --profile release --local --platform android --non-interactive --output /workspace/notifier.apk'
+  ```
+
 ## Configuration
 
 ### Backend URL