build docs on Travis :fingers_crossed:

.travis.yml

@@ -10,6 +10,7 @@ env:
     - secure: "KcGydAqL7ryDh2rTJJB4wU8NE5BRtnrRXDEcPBScSscO3zFsHXHBDvvO04B/9hFVatXzGYXmkn+FZ0P9QikhvebzdwwyqUG2SKFiHhMvbX0m0WtAhn5NqDuKU1r5qy5YQ18r/tiLfC9GSAlEpfLAH58pwpcn8srV3Mn/yKvlrfs="
 
 script:
+  - script/build-docs
   - npm test
   - script/check-versions
 

script/build-docs

@@ -0,0 +1,9 @@
+#!/bin/sh
+cd docs
+npm install
+npm run prepare
+if [ -z "$NOW_TOKEN" ]; then
+    echo "NOW_TOKEN is not set; skipping docs deployment"
+else
+    now --token=$NOW_TOKEN
+fi