old_contents: from django.db import models
  
  class Classify(models.Model):
      name = models.CharField(max_length=20)
      def __unicode__(self):
          return self.name
  
  class Tag(models.Model):
      name = models.CharField(max_length=20)
      def __unicode__(self):
          return self.name
      
  class Article(models.Model):
      title = models.CharField(max_length=50)
      content = models.TextField()
      created_time = models.DateTimeField()
      classify = models.ForeignKey(Classify)
      tag = models.ForeignKey(Tag)
      
      class Meta:
          ordering = ['-created_time']
      def __unicode__(self):
          return self.title
      
  
new_contents: from django.db import models
  
  class Classify(models.Model):
      name = models.CharField(max_length=20)
      def __unicode__(self):
          return self.name
  
  class Tag(models.Model):
      name = models.CharField(max_length=20)
      def __unicode__(self):
          return self.name
      
  class Article(models.Model):
      title = models.CharField(max_length=50)
      content = models.TextField()
      created_time = models.DateTimeField()
      classify = models.ForeignKey(Classify)
      tag = models.ForeignKey(Tag)
      hits = models.IntegerField(max_length=1,null =False, blank=False,default=0)
      
      class Meta:
          ordering = ['-created_time']
      def __unicode__(self):
          return self.title
  
  class ImageClassify(models.Model):
      name = models.CharField(max_length=50)
      def __unicode__(self):
          return self.name    
  
  class Image(models.Model):
      image = models.ImageField(upload_to='images')
      description = models.CharField(max_length=255)
      image_classify = models.ForeignKey(ImageClassify)
      def __unicode__(self):
          return self.description
  
  
subject: add two models: ImageClassify, Image