Updated build

Author: Simon Hofmann

.travis.yml

@@ -45,6 +45,7 @@ script:
 
 after_success:
   - if [[ $TRAVIS_TAG != "" ]]; then
+    npm install;
     npm run prebuild -- -u $GITHUB_TOKEN;
     npm run prebuild -- -r electron -u $GITHUB_TOKEN;
     npm run prebuild -- -r node-webkit -u $GITHUB_TOKEN;