How to also post the relation?

Hello,

I made a form where the user can post a comment for an article. I succeeded to send the comment and the user name, but I don’t know how I can send the relation with the article (id_post).

import React, { useState } from 'react'
import { useParams } from 'react-router-dom'
import TextField from '@material-ui/core/TextField';
import { Button } from '@material-ui/core'
import CommentsAPI from '../../Services/CommentsAPI'

export default function CommentForm() {

    const [comment, setComment] = useState({})
    const {id_post} = useParams()

    const handleSubmit = async (event) => {
        event.preventDefault();
        try {
            CommentsAPI.create(JSON.parse(`{"data":{"id":${id_post}, "attributes":${JSON.stringify(comment)}}}`))
        } catch (error) {
            console.log(error)
        }
    }

    const handleChange = (event) => {
        const {name, value} = event.currentTarget
        setComment({
            ...comment,
            [name]: value
        })
    }

    return (
        <form onSubmit={handleSubmit}>
            <div>
                <TextField 
                    id="pseudo" 
                    label="Pseudo" 
                    type="text" 
                    onChange={handleChange}
                    name="pseudo"
                />
            </div>
            <div>
                <TextField
                    id="comment"
                    label="Comment"
                    multiline
                    minRows={2}
                    onChange={handleChange}
                    name="content"
                />
            </div>
            <div>
                <Button variant="contained" color="primary" type="submit">
                    Send
                </Button>
            </div>
        </form>
    )
}
import { URL_COMMENTS } from '../config'
import axios from 'axios'

function create(id_post, comment) {
    return axios.post(URL_COMMENTS, id_post, comment)
}

const CommentsAPI = {
    create
}

export default CommentsAPI

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