Added github build workflow

.github/workflows/build.yaml

@@ -0,0 +1,55 @@
+name: Build and Push Container
+
+on:
+  workflow_dispatch:
+  push:
+    branches: [ "main" ]
+    paths:
+      - "Dockerfile.production"
+      - "compose.prod.yaml"
+      - "requirements.txt"
+      - assets/
+      - reflex_gpt/
+      - rxconfig.py
+      - alembic.ini
+      - alembic/
+      - .github/workflows/build.yaml
+
+env:
+  # DOCKER_IMAGE: codingforentrepreneurs/reflex-gpt
+  # uncomment if using 
+  DOCKER_IMAGE: ${{ secrets.DOCKERHUB_REPO }}
+
+jobs:
+  build-and-push:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v4
+
+    - name: Set up Docker Buildx
+      uses: docker/setup-buildx-action@v2
+
+    - name: Login to DockerHub
+      uses: docker/login-action@v2
+      with:
+        username: ${{ secrets.DOCKERHUB_USERNAME }}
+        password: ${{ secrets.DOCKERHUB_TOKEN }}
+
+    # For Reflex to build a container,
+    # injecting your environment variables at 
+    # container build time is often required.
+    - name: Create build env file
+      run: |
+         cat << EOF > .build-env
+         OPENAI_API_KEY=${{ secrets.OPENAI_API_KEY }}
+         DATABASE_URL=${{ secrets.DATABASE_URL }}
+         EOF
+
+    - name: Build and push
+      run: |
+        docker build -f Dockerfile.production -t ${{ env.DOCKER_IMAGE }}:latest .
+        docker tag ${{ env.DOCKER_IMAGE }}:latest ${{ env.DOCKER_IMAGE }}:${{ github.sha }}
+        docker push ${{ env.DOCKER_IMAGE }} --all-tags
+
+    - name: Remove build env file
+      run: rm .build-env