Add build workflow

.github/workflows/build.yml

@@ -0,0 +1,25 @@
+name: Build
+
+on: [push, pull_request]
+
+jobs:
+  build:
+    runs-on: ubuntu-18.04
+
+    steps:
+    - uses: actions/checkout@v2
+
+    - name: Install GF
+      env:
+        GF_VERSION: 3.10-1
+      run: |
+        curl -s https://www.grammaticalframework.org/download/gf_${GF_VERSION}_amd64.deb -o gf.deb
+        dpkg -i gf.deb
+
+    - name: Build RGL
+      run: |
+        bash Setup.sh --dest=dist/ --gf= --verbose
+
+    # - uses: actions/upload-artifact@v2
+    #   with:
+    #     path: dist