Add CI workflow to build and test

Author: vrom911

.github/workflows/ci.yml

@@ -0,0 +1,49 @@
+name: CI
+
+on:
+  push:
+    branches:
+      - master
+  pull_request:
+    branches:
+      - master
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v4
+
+      - name: Install Nix
+        uses: cachix/install-nix-action@v25
+        with:
+          nix_path: nixpkgs=channel:nixos-unstable
+
+      - name: Setup Cachix
+        uses: cachix/cachix-action@v14
+        with:
+          name: iohk
+
+      - name: Build
+        run: nix build
+
+  test:
+    needs: build
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v4
+
+      - name: Install Nix
+        uses: cachix/install-nix-action@v25
+        with:
+          nix_path: nixpkgs=channel:nixos-unstable
+
+      - name: Setup Cachix
+        uses: cachix/cachix-action@v14
+        with:
+          name: iohk
+
+      - name: Test
+        run: nix flake check