Use 'Build and push Docker images' GitHub Action

.github/workflows/build.yml

@@ -0,0 +1,22 @@
+name: ci
+
+on:
+  push:
+    branches:
+      - main
+
+jobs:
+  docker:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Login to Docker Hub
+        uses: docker/login-action@v2
+        with:
+          username: ${{ secrets.DOCKERHUB_USERNAME }}
+          password: ${{ secrets.DOCKERHUB_TOKEN }}
+      - name: Build and push
+        uses: docker/build-push-action@v3
+        with:
+          context: .
+          push: true
+          tags: freeitathens/timetrex:latest