input: Write a python function to retrieve all users' information from the database.
  assert get_all_users() == [('John', 20, 'Male', 8054839479)]
  store_info("Jane", 25, "Female", 1234567890)
  assert get_all_users() == [('John', 20, 'Male', 8054839479), ('Jane', 25, 'Female', 1234567890)]
  store_info("Doe", 30, "Non-binary", 9876543210)
  assert get_all_users() == [('John', 20, 'Male', 8054839479), ('Jane', 25, 'Female', 1234567890), ('Doe', 30, 'Non-binary', 9876543210)]
output: users_db = []
  
  def store_info(name, age, gender, phone):
      users_db.append((name, age, gender, phone))
  
  def get_all_users():
      return users_db