Adds unit test CI.

.github/workflows/unit_tests.yml

@@ -0,0 +1,24 @@
+name: Unit tests
+
+on: [ push ]
+
+jobs:
+  unit-tests:
+    runs-on: ubuntu-latest
+    strategy:
+      max-parallel: 5
+
+    steps:
+      - uses: actions/checkout@v4
+      - name: "Setup Node.js"
+        id: setup-node
+        uses: actions/setup-node@v4
+        with:
+          node-version-file: .node-version
+          cache: npm
+      - name: "Install Dependencies"
+        id: install
+        run: cd contracts && npm ci
+      - name: "Backend Unit tests"
+        run: |
+          cd contracts && npm run test