Show alert if renaming/removing failed

src/app.js

@@ -272,10 +272,13 @@ var run = function () {
           files.exists(newName)
             ? 'Are you sure you want to overwrite: ' + newName + ' with ' + originalName + '?'
             : 'Are you sure you want to rename: ' + originalName + ' to ' + newName + '?')) {
-        files.rename(originalName, newName)
+        if (!files.rename(originalName, newName)) {
+          alert('Error while renaming file')
+        } else {
           switchToFile(newName)
           editor.discard(originalName)
         }
+      }
 
       return false
     }
@@ -289,10 +292,13 @@ var run = function () {
     var name = $(this).parent().find('.name').text()
 
     if (confirm('Are you sure you want to remove: ' + name + ' from local storage?')) {
-      files.remove(name)
+      if (!files.remove(name)) {
+        alert('Error while removing file')
+      } else {
         switchToNextFile()
         editor.discard(name)
       }
+    }
     return false
   })