old_contents: from django.contrib.auth.models import User
  from subprocess import Popen, PIPE
  
  
  class UosisMIFVUAuthBackend(object):
      def authenticate(self, username=None, password=None):
          login_check_cmd = """sshpass -p '%s' ssh -t -t -o \
  StrictHostKeyChecking=no %s@uosis.mif.vu.lt 'pwd'""" % (password, username)
          login_response = Popen(login_check_cmd, shell=True, stdout=PIPE,
                                                              stderr=PIPE)
          login_response.wait()
          if not login_response.communicate()[0]:
              return None
  
          try:
              user = User.objects.get(username=username)
          except User.DoesNotExist:
              user = User(username=username)
              user.is_staff = False
              user.is_superuser = False
              user.set_unusable_password()
              user.save()
          return user
  
      def get_user(self, id):
          try:
              return User.objects.get(id=id)
          except User.DoesNotExist:
              return None
  
new_contents: from django.db import models
  from django.contrib.auth.models import User
  
  
  class DatasetLicence(models.Model):
      title = models.CharField(max_length=255)
      short_title = models.CharField(max_length=30)
      url = models.URLField()
      summary = models.TextField()
      updated = models.DatetimeField(auto_now=True)
      created = models.DatetimeField(auto_now_add=True)
  
  
  class FileFormat(models.Model):
      extension = models.CharField(max_length=10)
      description = models.TextField()
      updated = models.DatetimeField(auto_now=True)
      created = models.DatetimeField(auto_now_add=True)
  
  
  class Dataset(models.Model):
      title = models.CharField(max_length=255)
      licence = models.ForeignKey('DatasetLicence')
      file = models.FileField()
      file_format = models.ForeignKey('FileFormat')
      description = models.TextField()
      author = models.ForeignKey(User)
      updated = models.DatetimeField(auto_now=True)
      created = models.DatetimeField(auto_now_add=True)
  
subject: Add Dataset model.