old_contents: from peewee import *
  import json
  
  with open("config.json") as f:
      config = json.load(f)
  
  db = PostgresqlDatabase(config["POSTGRES_USER"], host=config["POSTGRES_HOST"],
          user=config["POSTGRES_USER"],
          password=config["POSTGRES_PASSWORD"])
  
  class BaseModel(Model):
      class Meta:
          database = db
  
  class HistoricalTrainPosition(BaseModel):
      cars = IntegerField()
      line_code = CharField()
      next_station = CharField()
      dest_station = CharField()
      time = IntegerField()
      timestamp = DateTimeField()
  
new_contents: from peewee import *
  import json
  
  with open("config.json") as f:
      config = json.load(f)
  
  db = PostgresqlDatabase(config["POSTGRES_USER"], host=config["POSTGRES_HOST"],
          user=config["POSTGRES_USER"],
          password=config["POSTGRES_PASSWORD"])
  
  class BaseModel(Model):
      class Meta:
          database = db
  
  class HistoricalTrainPosition(BaseModel):
      cars = IntegerField()
      line_code = CharField()
      next_station = CharField()
      dest_station = CharField()
      time = IntegerField()
      timestamp = DateTimeField()
      trackgroup = IntegerField()
  
subject: fix models -> trackgroup