Add build github action

.github/workflows/build.yml

@@ -0,0 +1,26 @@
+name: Build
+
+on:
+  push:
+    branches:
+      - 'main'
+
+jobs:
+  docker:
+    runs-on: ubuntu-latest
+    steps:
+      -
+        name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v3
+      -
+        name: Login to GitHub Container Registry
+        uses: docker/login-action@v3
+        with:
+          registry: ghcr.io
+          username: ${{ github.actor }}
+          password: ${{ secrets.GITHUB_TOKEN }}
+      -
+        name: Build and push
+        uses: docker/build-push-action@v5
+        with:
+          push: true

Dockerfile

@@ -18,6 +18,9 @@ RUN curl -sS https://dl.yarnpkg.com/debian/pubkey.gpg | apt-key add -
 RUN echo "deb https://dl.yarnpkg.com/debian/ stable main" | tee /etc/apt/sources.list.d/yarn.list
 RUN apt update && apt install -y yarn
 
+COPY ./package.json ./yarn.lock /app/
+RUN yarn install
+
 COPY . /app
 
 RUN bundle exec rails assets:precompile