How to add comments to post in Flask application?

class Comment(Model):
    timestamp = DateTimeField(default=datetime.datetime.now)
    content = TextField()
    user = ForeignKeyField(
        rel_model=User,
        related_name='comments' 
        )
    post = ForeignKeyField(
        rel_model=Post,
        related_name='comments' 
        )

        class Meta:
        database = DATABASE
        order_by = ('-timestamp',) 

@app.route('/post')
@app.route('/post/<int:postid>')
def singlepost(postid=None):
    postNumber = request.args.get('post', postid)
    post = models.Post.select().where(models.Post.id == postNumber).get()

    form = forms.CommentForm()
    if form.validate_on_submit():
        models.Comment.create(content=form.content.data.strip(), post=post._get_current_object() , user=g.user._get_current_object())
        flash("Comment posted!", 'alert-success')
        return redirect(url_for('singlepost'))

    return render_template("singlepost.html", post=post, form=form)

{% extends "base.html" %}
{% from 'macros.html' import render_field %} 

{% block page_content %}

    <article>
        <h6>
            Post by <a href="{{ url_for('stream', username=post.user.username)}}"> 
                        {{ post.user.name}}
                    </a>
            <span style="float:right; clear:right; ">at {{ post.timestamp.strftime('%d-%m-%Y %H:%M')}}</span>

        </h6>

        <div class='post'>

            <div style="width: 100%; display: inline-block;">
                <h4> 
                    <a href="{{ url_for('singlepost', post=post.id) }}"> 
{{ post.content}} </a> 
                </h4>

            </div>

        </div>
        <hr>
    </article>

    <!-- comment section -->

    <form class="form form-horizontal col-md-12" method="post" role="form">

    {{ form.hidden_tag() }}  <!-- Renders hidden fields inside of a hidden <div>. -->
    {% for field in form %} <!-- it will help us loop through the elements in our forms.py -->
        {{ render_field(field) }} <!-- We used the maco we created to render the feild -->
    {% endfor %}
    <br>
    <br>
        <button type='submit' class="btn btn-primary" id='submit'>Submit</button>
</form>

{% endblock %}