Add workflows and gitignore

.github/workflows/check-flake.yml

@@ -0,0 +1,19 @@
+name: check-flake
+
+on: [push, pull_request, workflow_dispatch]
+
+jobs:
+  checks:
+    name: Check expressions
+    runs-on: ubuntu-latest
+
+    steps:
+      - uses: actions/checkout@v4
+      - uses: cachix/install-nix-action@v25
+        with:
+          install_url: https://nixos.org/nix/install
+          extra_nix_config: |
+            auto-optimise-store = true
+            access-tokens = github.com=${{ secrets.GITHUB_TOKEN }}
+            experimental-features = nix-command flakes
+      - run: nix flake check

.github/workflows/update-flake.yml

@@ -0,0 +1,21 @@
+name: update-flake-lock
+on:
+  workflow_dispatch: # allows manual triggering
+  schedule:
+    - cron: '0 0 * * *' # runs weekly on Sunday at 00:00
+  push:
+      paths:
+        - 'flake.nix'
+jobs:
+  lockfile:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v4
+      - name: Install Nix
+        uses: cachix/install-nix-action@v25
+        with:
+          extra_nix_config: |
+            access-tokens = github.com=${{ secrets.GITHUB_TOKEN }}
+      - name: Update flake.lock
+        uses: DeterminateSystems/update-flake-lock@v21

.gitignore

@@ -0,0 +1,19 @@
+# Ignore everything
+*
+
+# But don't ignore folders
+!*/
+
+# But don't ignore these types of files
+!*.nix
+!*.yml
+!*.lock
+
+# Don't ignore the README
+!README.md
+
+# Don't ignore LICENSE and github actions
+!LICENSE
+!.github/workflows
+
+# Ignore files larger than 100M