input: Write a function to design a web server in Python using the Flask framework that serves a JSON object containing the current temperature for a city based on the city name provided in the request. The function should include the necessary Flask route and logic to fetch and return the temperature from an external API.
  
  assert design_server() == \
  """import requests
  import json
  
  from flask import Flask, request
  
  app = Flask(__name__)
  
  @app.route('/getTemp', methods=['POST'])
  def get_temp():
   city = request.json['city']
   url = 'http://api.openweathermap.org/data/2.5/weather?q={}&APPID=xxxxxx'
   r = requests.get(url.format(city))
   weather = json.loads(r.text)
   return {'temperature': weather['main']['temp']}
  
  if __name__ == '__main__':
   app.run(debug=True)
  """
output: 
  import requests
  import json
  
  from flask import Flask, request
  
  app = Flask(__name__)
  
  @app.route('/getTemp', methods=['POST'])
  def get_temp():
   city = request.json['city']
   url = 'http://api.openweathermap.org/data/2.5/weather?q={}&APPID=xxxxxx'
   r = requests.get(url.format(city))
   weather = json.loads(r.text)
   return {'temperature': weather['main']['temp']}
  