enable devtools

lib/main-menu.js

@@ -146,6 +146,14 @@ var view = {
       click: function () {
         BrowserWindow.getFocusedWindow().reload()
       }
+    },
+    {
+      label: 'Toggle Developer Tools',
+      accelerator: process.platform === 'darwin' ? 'Alt+Command+I' : 'Ctrl+Shift+I',
+      click(item, focusedWindow) {
+        if (focusedWindow)
+          focusedWindow.webContents.toggleDevTools();
+      }
     }
   ]
 }