code: def add_user(self, username, password, full_name=None, trusted=False, readonly=False):
          
  
          # generate salt
          char_set = string.ascii_letters + string.digits
          salt = ''.join(random.choice(char_set) for x in range(8))
  
  
          sql = '''INSERT INTO user
              (username, pwd_salt, pwd_hash, full_name, trusted, readonly)
              VALUES
              (?, ?, ?, ?, ?, ?)'''
          try:
              self._db_curs.execute(sql, (username, salt,
                  self._gen_hash(password, salt), full_name, trusted or False,
                                          readonly or False))
              self._db_conn.commit()
          except (sqlite3.OperationalError, sqlite3.IntegrityError) as error:
              raise AuthError(error)
docs: Add user to SQLite database.
  
              * `username` [string]
                  Username of new user.
              * `password` [string]
                  Password of new user.
              * `full_name` [string]
                  Full name of new user.
              * `trusted` [boolean]
                  Whether the new user should be trusted or not.
              * `readonly` [boolean]
                  Whether the new user can only read or not