ci(CircleCI): switch from Travis CI to CircleCI

.circleci/config.yml

@@ -0,0 +1,21 @@
+# https://circleci.com/docs/2.0/language-javascript/
+version: 2
+jobs:
+  build:
+    docker:
+      - image: circleci/node:8
+    working_directory: ~/typescript-starter
+    steps:
+      - checkout
+      # Download and cache dependencies
+      - restore_cache:
+          keys:
+          - v1-dependencies-{{ checksum "package.json" }}
+          # fallback to using the latest cache if no exact match is found
+          - v1-dependencies-
+      - run: npm install
+      - save_cache:
+          paths:
+            - node_modules
+          key: v1-dependencies-{{ checksum "package.json" }}
+      - run: npm test