Add support for automatic publishing to the npm registry upon pushing tags. (#5)

Author: alrik

.travis.yml

@@ -7,8 +7,17 @@ node_js:
 cache: yarn
 git:
   depth: 3
+script:
+- yarn validate-schema
+
 jobs:
   include:
-  - stage: test
-    script:
-    - yarn validate-schema
+  - stage: publish
+    node_js: "8"
+    script: echo "publish to npm"
+    deploy:
+      provider: npm
+      email: [email protected]
+      api_key: $NPM_API_KEY
+      on:
+        tags: true