从首页问答标题到问答详情页

1. 主PY文件写视图函数，带id参数。 

   @app.route('/detail/<question_id>')
   def detail(question_id):
       quest = 
       return render_template('detail.html', ques = quest) 

2. 首页标题的标签做带参数的链接。
         {{ url_for('detail',question_id = foo.id) }}
   
   
3. 在详情页将数据的显示在恰当的位置。 

   {{ ques.title}}
   {{ ques.id  }}{{  ques.creat_time }}

   {{ ques.author.username }} 
   {{ ques.detail }}

4. 建立评论的对象关系映射：

   class Comment(db.Model):
       __tablename__='comment'

5.  尝试实现发布评论。

   @app.route('/detail/<qusetion_id>')
   def detail(question_id):
       quest=Question.query.filter(Question.id==question_id).first()
       return render_template('detail.html',ques=quest)

   <div>
           <ul class="news-list">
               {% for foo in questions %}
                   <li class="list-group-item">
                       <span class="glyphicon glyphicon-leaf" aria-hidden="true"></span>
                       <a href="{{ url_for('detail',question_id=foo.id) }}" class="title">{{ foo.title }}</a>
                       <p class="detail">{{ foo.detail }}</p>
                       <span class="glyphicon glyphicon-leaf" aria-hidden="true"></span>
                       <a href="#">{{ foo.author.username }}</a>
                       <span class="badge">{{ foo.creat_time }}</span>
                   </li>
               {% endfor %}
           </ul>
       </div>

   <div class="page-header">
       <h3>{{ques.title}}<br><small>{{ques.author.username}} <span class="badge">{{ques.creat_time}}</span> </small></h3>
   </div>
   <p class="lead">{{ques.detail}}</p>
   <hr>
   <form action="{{url_for('question')}}"method="post">
       <div class="form-group">
           <textarea name="new_comment"class="form-control"rows="3"id="new-comment"placeholder="write your comment"></textarea>
       </div>
       <button type="submit"class="btn btn-default">发送</button>
   </form>
   <ul class="list-group"style="margin:10px"></ul>

   class Comment(db.Model):
       __tablename__='comment'
       id = db.Column(db.Integer, primary_key=True, autoincrement=True)
       author_id = db.Column(db.Integer, db.ForeignKey('user.id'))
       question_id=db.Column(db.Integer, db.ForeignKey('question.id'))
       create_time = db.Column(db.DateTime, default=datetime.now)
       detail = db.Column(db.Text, nullable=False)
       question=db.relationship('Question',backref=db.backref('comments'))
       author=db.relationship('User',backref=db.backref('comments'))