Attempt to build gospel config

.forgejo/workflows/demo.yaml

@@ -4,7 +4,7 @@ on: [push]
 
 jobs:
   Explore-Forgejo-Actions:
-    runs-on: ubuntu-latest
+    runs-on: nix-builder
     steps:
       - run: echo "🎉 The job was automatically triggered by a ${{ forgejo.event_name }} event."
       - run: echo "🐧 This job is now running on a ${{ runner.os }} server hosted by Forgejo!"
@@ -16,4 +16,5 @@ jobs:
       - name: List files in the repository
         run: |
           ls ${{ forgejo.workspace }}
+      - run: nix build .#nixosConfigurations.gospel.config.system.build.toplevel
       - run: echo "🍏 This job's status is ${{ job.status }}."