input: Write a python function to create a new task, retrieve all tasks, and update a task description using Flask and SQLAlchemy.
  assert create_task('Test Task 1') == {'id': 1}
  assert get_tasks() == {'tasks': ['Test Task 1']}
  assert update_task(1, 'Updated Task 1') == {'message': 'Task updated'}
  assert get_tasks() == {'tasks': ['Updated Task 1']}
output: from flask import Flask, request, jsonify
  from flask_sqlalchemy import SQLAlchemy
  
  app = Flask(__name__)
  app.config['SQLALCHEMY_DATABASE_URI'] = 'sqlite:///tasks.db'
  db = SQLAlchemy(app)
  
  class Task(db.Model):
      id = db.Column(db.Integer, primary_key=True)
      description = db.Column(db.String(200), nullable=False)
  
  db.create_all()
  
  def create_task(description):
      new_task = Task(description=description)
      db.session.add(new_task)
      db.session.commit()
      return {'id': new_task.id}
  
  def get_tasks():
      tasks = Task.query.all()
      return {'tasks': [task.description for task in tasks]}
  
  def update_task(task_id, new_description):
      task = Task.query.get(task_id)
      if task:
          task.description = new_description
          db.session.commit()
          return {'message': 'Task updated'}
      return {'message': 'Task not found'}