Use Docker on GH action

.github/workflows/main.yml

@@ -0,0 +1,24 @@
+name: main
+
+on:
+  pull_request:
+    types: [opened, reopened, synchronize]
+  push:
+    branches: [master]
+
+run-name: ${{ github.workflow }} | ${{ github.event.pull_request.number }} ${{ github.event.pull_request.title || github.event.head_commit.message }}
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+
+    steps:
+    - name: Checkout
+      uses: actions/checkout@v2
+
+    - name: Build
+      run: docker build --tag nix-package-versions .
+      working-directory: ./
+
+    - name: Test
+      run: docker run nix-package-versions ./utils.sh test

utils.sh

@@ -17,17 +17,17 @@ function watch-test {
   ghcid -c 'cabal v2-repl' nix-package-versions-test
 }
 
+function test {
+  cabal v2-run nix-package-versions-test
+}
+
 function server {
   cabal v2-run nix-package-versions-exe -- \
     server \
     --port 8080 \
     --db-root database
 }
 
-function test {
-  cabal v2-run nix-package-versions-test
-}
-
 function update-database {
   # Load GitHub credentials
   source $(pwd)/.secrets