old_contents: import os
  
  DEBUG = True
  SECRET_KEY = 'dev'
  
  root = os.path.abspath(os.path.dirname(__file__))
  SQLALCHEMY_DATABASE_URI = 'sqlite:///' + os.path.join(root, 'sqlite3.db')
  
new_contents: import os
  
  DEBUG = True
  SECRET_KEY = 'dev'
  
  if DEBUG:
      root = os.path.abspath(os.path.dirname(__file__))
      SQLALCHEMY_DATABASE_URI = 'sqlite:///' + os.path.join(root, 'sqlite3.db')
  else:
      db = 'database'
      username = 'username'
      password = 'password'
      uri = 'postgres://%s:%s@localhost:5432/%s' % (username, password, db)
      SQLALCHEMY_DATABASE_URI = uri
  
subject: add postgresql settings for production server