Add GitHub Actions workflow for Izem Runtime CI

.github/workflows/nim-ci.yml

@@ -0,0 +1,35 @@
+name: Izem Runtime CI
+
+on:
+  push:
+    branches: [ master ]
+  pull_request:
+    branches: [ master ]
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+
+    steps:
+    - uses: actions/checkout@v2
+
+    - name: Set up Nim
+      uses: iffy/install-nim@v5
+      with:
+        version: '2.0.0'
+
+    - name: Install system dependencies
+      run: |
+        sudo apt-get update
+        sudo apt-get install -y libwebkit2gtk-4.0-dev
+
+    - name: Install nim dependencies
+      run: make deps
+
+    - name: Build project
+      run: make
+
+    - name: Run basic test
+      run: |
+        echo 'console.log("Hello, World!");' > test.js
+        ./izem test.js | grep "Hello, World!"