moved some validation from settings page to form.

comic/forms.py

@@ -1,5 +1,8 @@
 from django import forms
 from django.contrib.auth.models import User
+
+from os import path
+
 from comic.models import Setting
 
 
@@ -174,6 +177,12 @@ class SettingsForm(forms.Form):
                                                 }
                                             ))
 
+    def clean_base_dir(self):
+        data = self.cleaned_data['base_dir']
+        if not path.isdir(data):
+            raise forms.ValidationError('This is not a valid Directory')
+        return data
+
     @staticmethod
     def get_initial_values():
         base_dir, created = Setting.objects.get_or_create(name='BASE_DIR')