process.php

 <?php
 require("config/config.php");
 require("lib/db.php");
 $conn = db_init($config["host"], $config["duser"], $config["dpw"], $config["dname"]);


 $title = mysqli_real_escape_string($conn, $_POST['title']);
 $author = mysqli_real_escape_string($conn, $_POST['author']);
 $description = mysqli_real_escape_string($conn, $_POST['description']);

 $sql = "SELECT * FROM user WHERE name='".$author."'";
 $result  = mysqli_query($conn, $sql);
 if($result->num_rows == 0){
   $sql = "INSERT INTO user (name, password) VALUES('".$author."', '111111')";
   mysqli_query($conn, $sql);
   $user_id = mysqli_insert_id($conn);
 } else {
   $row = mysqli_fetch_assoc($result);
   $user_id = $row['id'];
 }
 $sql = "INSERT INTO topic (title,description,author,created) VALUES('".$title."', '".$description."', '".$user_id."', now())";
 $result = mysqli_query($conn, $sql);
 header('Location: http://localhost/index.php');
 ?>