Create CI build script.

.github/workflows/main.yml

@@ -0,0 +1,41 @@
+name: CI Build Test
+
+on: [push]
+
+jobs:
+  build:
+
+    runs-on: ubuntu-latest
+
+    steps:
+    - uses: actions/checkout@v1
+      with:
+        fetch-depth: 1
+
+    - name: Clean repo of artifacts
+      run: git clean -f
+
+    - name: Cache tup build dependency
+      id: cache-tup
+      uses: actions/cache@v1
+      with:
+        path: "${HOME}/dependencies/gittup"
+        key: ${{ runner.OS }}-gittup
+
+    - name: Install tup build dependency
+      if: steps.cache-tup.outputs.cache-git != 'true'
+      run: |
+        sudo apt install libfuse-dev
+        cd "${HOME}"
+        git clone https://github.com/gittup/tup.git dependencies/gittup
+        cd dependencies/gittup
+        ./build.sh
+        ./bootstrap.sh
+
+    - name: Install gmp library
+      run: sudo apt-get install libgmp-dev
+
+    - name: Run a build
+      run: |
+        "${HOME}/dependencies/gittup/build/tup" init
+        "${HOME}/dependencies/gittup/build/tup"