Added integration with GitHub pipelines.

Closes #23.

.github/workflows/linux.yml

@@ -0,0 +1,27 @@
+name: Linux CI
+
+on:
+  push:
+    branches: [ master ]
+  pull_request:
+    branches: [ master ]
+
+jobs:
+  build:
+
+    runs-on: ubuntu-latest
+
+    steps:
+    - uses: actions/checkout@v2
+    - name: install requirements
+      run: |
+        sudo apt-get update
+        sudo apt-get -y install g++ cmake make
+    - name: fetch submodules
+      run: git submodule update --init --recursive
+    - name: cmake build
+      run: |
+        mkdir build
+        cd build
+        cmake ..
+        cmake --build .