👷 Add build step

Add backend build step

.circleci/config.yml

@@ -0,0 +1,24 @@
+version: 2
+jobs:
+  build: &shared-config
+    docker:
+      - image: circleci/node:lts-fermium
+    working_directory: ~/repo
+    steps:
+      - checkout
+      - restore_cache:
+          keys:
+            - dependencies-{{ checksum "package.json" }}-v1
+            # fallback to using the latest cache if no exact match is found
+            - dependencies-
+      - run: yarn install
+      - save_cache:
+          paths:
+            - node_modules
+          key: dependencies-{{ checksum "package.json" }}-v1
+
+workflows:
+  version: 2
+  build-test-and-lint:
+    jobs:
+      - build