Change TravisCI rules to regulate only OSX

Author: Umius-Brian

.travis.yml

@@ -1,5 +1,10 @@
 language: node_js
 node_js: 
   - "stable"
+os:
+  osx
+jobs:
+  allow_failures:
+    - os: osx
 install:
   - npm install

Main.js

@@ -75,7 +75,7 @@ app.on('window-all-closed', () => {
     { encoding: 'UTF-8' }
   );
   // process platform is a property that return a string identifying the OS platform on which NodeJs process is running --> Ousman
-  if (process.platform !== 'linux') {
+  if (process.platform !== 'darwin') {
     // quits application
     app.quit();
   }