revert: circle ci removal

This reverts commit 3d26c68.

Author: kiaking

.circleci/config.yml

@@ -0,0 +1,36 @@
+version: 2
+
+step_restore_cache: &restore_cache
+  restore_cache:
+    keys:
+    - v1-dependencies-{{ checksum "yarn.lock" }}-1
+    - v1-dependencies-
+
+step_install_deps: &install_deps
+  run:
+    name: Install Dependencies
+    command: yarn --frozen-lockfile
+
+step_save_cache: &save_cache
+  save_cache:
+    paths:
+      - node_modules
+      - ~/.cache/yarn
+    key: v1-dependencies-{{ checksum "yarn.lock" }}-1
+
+jobs:
+  test:
+    docker:
+      - image: circleci/node:12
+    steps:
+      - checkout
+      - *restore_cache
+      - *install_deps
+      - *save_cache
+      - run: yarn test
+
+workflows:
+  version: 2
+  ci:
+    jobs:
+      - test