ci: added travis ci config file

Author: IjzerenHein

.travis.yml

@@ -0,0 +1,8 @@
+language: node_js
+node_js:
+  - '8'
+  - '10'
+  - '12'
+install: yarn
+script:
+  - yarn test

package.json

@@ -27,7 +27,7 @@
   },
   "scripts": {
     "test": "yarn test:rn61 && yarn test:expo35",
-    "test:rn61": "cd test/RN61 && npx ../.. && cd ../..",
-    "test:expo35": "cd test/Expo35 && npx ../.. && cd ../.."
+    "test:rn61": "cd test/RN61 && yarn install && npx ../.. && cd ../..",
+    "test:expo35": "cd test/Expo35 && yarn install && npx ../.. && cd ../.."
   }
 }