first stab at a github workflow

.github/workflows/ubuntu_test.yml

@@ -0,0 +1,50 @@
+---
+name: Ubuntu
+
+on:
+  pull_request:
+  push:
+    branches:
+      - master
+
+jobs:
+  tests:
+    env:
+      COLORTERM: truecolor
+      NPROC: 2
+      TERM: xterm
+    name: 🐧 build, test, & install
+    runs-on: ubuntu-latest
+
+    steps:
+
+      - name: Install tools and libraries via APT
+        run: |
+          sudo apt update
+          sudo apt install -y \
+            build-essential \
+            cmake \
+            nettle-dev
+
+      - uses: actions/checkout@v2
+
+      - name: cmake
+        run: |
+          mkdir build && cd build
+          cmake .. \
+            -DCMAKE_BUILD_TYPE=Release
+
+      - name: make
+        run: |
+          cd build
+          make -j${NPROC}
+
+      - name: ctest
+        run: |
+          cd build
+          ctest --output-on-failure
+
+      - name: make install
+        run: |
+          cd build
+          sudo make install