Add CI workflow

.github/workflows/ci.yml

@@ -0,0 +1,79 @@
+name: CI
+
+on:
+  push:
+    branches:
+      - main
+  pull_request:
+    branches:
+      - main
+
+jobs:
+  build:
+    strategy:
+      matrix:
+        os: [ubuntu-latest, windows-latest]
+        flutter_channel: [stable]
+    runs-on: ${{ matrix.os }}
+    steps:
+      - uses: actions/checkout@v2
+
+      - name: Install CMake and Ninja
+        if: matrix.os == 'ubuntu-latest'
+        run: sudo apt-get install -y cmake ninja-build
+
+      - name: Install GTK and pkg-config (Ubuntu)
+        if: matrix.os == 'ubuntu-latest'
+        run: sudo apt-get install -y libgtk-3-dev pkg-config
+
+      - name: Setup Flutter
+        uses: subosito/flutter-action@v2
+        with:
+          flutter-version: '3.16.5'
+
+      - name: Install dependencies
+        run: flutter pub get
+
+      - name: Build Web
+        if: matrix.os == 'ubuntu-latest'
+        run: flutter build web
+
+      - name: Upload Web Artifact
+        if: matrix.os == 'ubuntu-latest'
+        uses: actions/upload-artifact@v2
+        with:
+          name: web-build
+          path: app/build/web
+
+      - name: Build Android
+        if: matrix.os == 'ubuntu-latest'
+        run: flutter build apk        
+
+      - name: Upload Android Artifact
+        if: matrix.os == 'ubuntu-latest'
+        uses: actions/upload-artifact@v2
+        with:
+          name: android-apk
+          path: app/build/app/outputs/flutter-apk/app-release.apk
+
+      - name: Build Windows
+        if: matrix.os == 'windows-latest'
+        run: flutter build windows
+
+      - name: Upload Windows Artifact
+        if: matrix.os == 'windows-latest'
+        uses: actions/upload-artifact@v2
+        with:
+          name: windows-build
+          path: app/build/windows/runner/Release
+
+      - name: Build Linux
+        if: matrix.os == 'ubuntu-latest'
+        run: flutter build linux
+
+      - name: Upload Linux Artifact
+        if: matrix.os == 'ubuntu-latest'
+        uses: actions/upload-artifact@v2
+        with:
+          name: linux-build
+          path: app/build/linux/x64/release/bundle