Let the Django FileField overwrite files with the same name

models.py

# -*- coding: utf-8 -*-
from django.conf import settings
from django.core.files.storage import FileSystemStorage
from django.db import models

class OverwriteStorage(FileSystemStorage):
    '''
    Muda o comportamento padrão do Django e o faz sobrescrever arquivos de
    mesmo nome que foram carregados pelo usuário ao invés de renomeá-los.
    '''
    def get_available_name(self, name):
        if self.exists(name):
            os.remove(os.path.join(settings.MEDIA_ROOT, name))
        return name

class Media(models.Model):
    name = models.CharField(u"Nome", max_length=128))
    media = models.FileField(u"Arquivo", upload_to=settings.MEDIA_DIR, storage=OverwriteStorage())