Create build.yml

.github/workflows/build.yml

@@ -0,0 +1,32 @@
+name: Flarum Build
+
+on:
+  push:
+    branches:
+      - main
+
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Check out code
+        uses: actions/checkout@v3
+
+      - name: Restore npm cache
+        uses: actions/cache@v3
+        with:
+          path: ~/.npm
+          key: ${{ runner.os }}-node-${{ hashFiles('js/package-lock.json') }}
+          restore-keys: |
+            ${{ runner.os }}-node-
+      # Our action will install npm, cd into `./js`, run `npm run build` and
+      # `npm run build-typings`, then commit and upload any changes
+      - name: Build production JS
+        uses: flarum/action-build@v3
+        with:
+          github_token: ${{ secrets.GITHUB_TOKEN }}
+          build_script: build
+          package_manager: yarn
+