old_contents: from django.db import models
  
  # Create your models here.
  
new_contents: from django.db import models
  
  
  class Researcher(models.Model):
      # TODO: username
      # TODO: password
      # TODO: email
      pass
  
  
  class Review(models.Model):
      user = models.ForeignKey(Researcher)
      title = models.CharField(max_length=128)
      description = models.TextField()
      query = models.CharField()
      date_created = models.DateTimeField(auto_now_add=True)
      last_modified = models.DateTimeField(auto_now=True)
  
  
  class Paper(models.Model):
      title = models.CharField()
      abstract = models.TextField()
      author = models.CharField()
      publish_date = models.DateField()
      url = models.URLField()
  
      ABSTRACT_STAGE = 'A'
      DOCUMENT_STAGE = 'D'
      FINAL_STAGE = 'F'
      STAGES = ((ABSTRACT_STAGE, 'Abstract stage'),
                (DOCUMENT_STAGE, 'Document stage'),
                (FINAL_STAGE, 'Final stage'))
  
      stage = models.CharField(max_length=1, choices=STAGES, default=ABSTRACT_STAGE)
  
subject: Create models