chore: add travis (#27)

.circleci/config.yml

@@ -1,22 +0,0 @@
-version: 2
-jobs:
-  build:
-    docker:
-      - image: circleci/node:9.4
-    working_directory: ~/repo
-
-    steps:
-      - checkout
-      - restore_cache:
-          keys:
-          - v1-dependencies-{{ checksum "package.json" }}
-          - v1-dependencies-
-      - run: yarn install
-      - save_cache:
-          paths:
-            - node_modules
-          key: v1-dependencies-{{ checksum "package.json" }}
-
-      - run: |
-          yarn lint
-          yarn build

.travis.yml

@@ -0,0 +1,6 @@
+language: node_js
+node_js:
+  - 10.8.0
+script:
+  - npm run lint
+  - npm run build