ci: add build action

.github/workflows/build.yml

@@ -0,0 +1,49 @@
+name: Build
+
+on:
+  push:
+    branches:
+    - master
+  pull_request:
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v4
+    - uses: actions-rust-lang/setup-rust-toolchain@v1
+      with:
+        toolchain: 1.74.0
+    - name: Cache WASI VFS
+      id: cache-wasi-vfs
+      uses: actions/cache@v4
+      with:
+        path: /usr/local/bin/wasi-vfs
+        key: ${{ runner.os }}-wasi-vfs
+    - uses: ruby/setup-ruby@v1
+      with:
+        ruby-version: 3.2
+        bundler-cache: true
+    - uses: actions/setup-node@v4
+      with:
+        cache: yarn
+    - name: Install wasi-vfs
+      if: steps.cache-wasi-vfs.outputs.cache-hit != 'true'
+      run: |
+        curl -LO "https://github.com/kateinoigakukun/wasi-vfs/releases/download/v0.5.2/wasi-vfs-cli-x86_64-unknown-linux-gnu.zip"
+        unzip wasi-vfs-cli-x86_64-unknown-linux-gnu.zip
+        mv wasi-vfs /usr/local/bin/wasi-vfs
+    - name: Cache ruby.wasm artefacts
+      id: cache-ruby-wasm
+      uses: actions/cache@v4
+      with:
+        path: |
+          build
+          rubies
+        key: ${{ runner.os }}-ruby-wasm
+    - name: Build ruby.wasm
+      run: |
+        bundle exec rbwasm build -o src/ruby.wasm --ruby-version 3.2
+    - name: Build web app
+      run: |
+        yarn build