old_contents: from application import db
  
  class User(db.Document):
      email = db.EmailField(required=True)
      alias = db.StringField(required=True)
      password = db.StringField(required=True)
      emailVerified = db.BooleanField(default=False)
      lastLogin = db.DateTimeField()
      allowTracking = db.BooleanField(default=False)
  
  class Posts(db.Document):
      #max length of title is 140 characters
      title = db.StringField(required=True, max_length=140)
      author= db.ReferenceField(User)
      #max length of content is 10000 characters
      content= db.StringField(max_length=10000)
      score = db.IntField(default=0)
  
  class Following(db.Document):
      user = db.ReferenceField(User)
      following = db.ListField(db.ReferenceField(User))
  
  class Kicked(db.Document):
      alias = db.StringField(required=True)
      ends = db.DateTimeField(required=True)
  
  class Banned(db.Document):
      email = db.EmailField(required=True)
  
new_contents: from application import db
  
  class User(db.Document):
      email = db.EmailField(required=True)
      alias = db.StringField(required=True)
      password = db.StringField(required=True)
      emailVerified = db.BooleanField(default=False)
      lastLogin = db.DateTimeField()
      allowTracking = db.BooleanField(default=False)
  
  class Posts(db.Document):
      #max length of title is 140 characters
      title = db.StringField(required=True, max_length=140)
      author= db.ReferenceField(User)
      #max length of content is 10000 characters
      content= db.StringField(max_length=10000)
      score = db.IntField(default=0)
  
  class Following(db.Document):
      user = db.ReferenceField(User)
      following = db.ListField(db.ReferenceField(User))
  
  class Kicked(db.Document):
      user = db.ReferenceField(User)
      ends = db.DateTimeField(required=True)
  
  class Banned(db.Document):
      email = db.EmailField(required=True)
  
subject: use user object not alias in class kicked