Added steps to build inside Docker

Dockerfile

@@ -0,0 +1,38 @@
+FROM node:22-bookworm
+
+ARG CMDLINE_TOOLS_VERSION=15859902
+ARG ANDROID_PLATFORM=android-36
+ARG ANDROID_BUILD_TOOLS=36.0.0
+ARG ANDROID_NDK=27.1.12297006
+
+RUN apt-get update && apt-get install -y --no-install-recommends \
+      openjdk-17-jdk-headless unzip curl ca-certificates git \
+    && rm -rf /var/lib/apt/lists/* \
+    && ln -s "$(dirname "$(dirname "$(readlink -f "$(which javac)")")")" /opt/java17
+
+ENV JAVA_HOME=/opt/java17 \
+    ANDROID_HOME=/opt/android-sdk \
+    GRADLE_USER_HOME=/home/node/.gradle \
+    CI=1
+ENV ANDROID_SDK_ROOT=$ANDROID_HOME
+ENV PATH=$JAVA_HOME/bin:$ANDROID_HOME/cmdline-tools/latest/bin:$ANDROID_HOME/platform-tools:$PATH
+
+RUN mkdir -p "$ANDROID_HOME/cmdline-tools" \
+    && curl -fsSL -o /tmp/cmdline-tools.zip \
+       "https://dl.google.com/android/repository/commandlinetools-linux-${CMDLINE_TOOLS_VERSION}_latest.zip" \
+    && unzip -q /tmp/cmdline-tools.zip -d "$ANDROID_HOME/cmdline-tools" \
+    && mv "$ANDROID_HOME/cmdline-tools/cmdline-tools" "$ANDROID_HOME/cmdline-tools/latest" \
+    && rm /tmp/cmdline-tools.zip \
+    && yes | sdkmanager --licenses > /dev/null \
+    && sdkmanager "platform-tools" "platforms;${ANDROID_PLATFORM}" \
+       "build-tools;${ANDROID_BUILD_TOOLS}" "ndk;${ANDROID_NDK}" \
+    && chown -R node:node "$ANDROID_HOME"
+
+RUN npm install -g eas-cli \
+    && mkdir -p "$GRADLE_USER_HOME" && chown -R node:node /home/node \
+    # mounted repos are owned by a different uid; stop git complaining
+    && git config --system --add safe.directory '*'
+
+USER node
+WORKDIR /workspace
+CMD ["bash"]

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