create.php

<?php
    // Headers
    header('Access-Control-Allow-Origin: *');
    header('Content-Type: application/json');
    header('Access-Control-Allow-Methods: POST');
    header('Access-Control-Allow-Headers: Access-Control-Allow-Headers, Content-Type, Access-Control-Allow-Methods, Authorization, X-Requested-With');

    include_once '../../config/Database.php';
    include_once '../../models/Players.php';

    // Instantiate DB & connect
    $database = new Database();
    $db = $database->connect();

    // Instantiate tournament object
    $players = new Players($db);

    // Get the raw posted data
    $data = json_decode(file_get_contents("php://input"));

    $players->playername = $data->playername;
    $players->clubname = $data->clubname;
    $players->gender = $data->gender;
    $players->dob = $data->dob;
    $players->ageGroupId = $data->ageGroupId;
    $players->weightCategoryId = $data->weightCategoryId;

    // Create player
    if($players->create()){
        echo json_encode()(
            array('message' => 'Player Created')
        );
    } else {
        echo json_encode()(
            array('message' => 'Player Is Not Created')
        );
    }

Database.php

<?php 
	class Database {
		// DB Parameters
		private $host = 'localhost';
		private $db_name = 'tournamentProject';
		private $username = 'root';
		private $password = '';
		private $conn;

		// DB Connect
		public function connect(){
			$this->conn = null;

			try {
				$this->conn = new PDO('mysql:host=' . $this->host . ';dbname=' . $this->db_name,
				$this->username, $this->password);
				$this->conn->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
			} catch(PDOException $e){
				echo 'Connection Error: ' . $e->getMessage();
			}

			return $this->conn;
		} 

	}

Players.php

<?php
	class Players{
		// DB Stuff
		private $conn;
		private $table = 'players';

		// Properties
		public $id;
		public $playername;
		public $clubname;
		public $gender;
		public $dob;
		public $ageGroupId;
		public $weightCategoryId;

		// Constructor with DB
		public function __construct($db){
			$this->conn = $db;
		}

		// Get Tournament
		public function read(){
			// Create query

			echo 'SELECT * from players';

			$query = 'SELECT id, playername, clubname, gender, dob, ageGroupId, weightCategoryId
					FROM
					' . $this->table . '
					';
			// Prepare statement
			$stmt = $this->conn->prepare($query);

			// Execute query
			$stmt->execute();

			return $stmt;
		}

		// Create Players
		public function create(){
			// Create query
			$query = 'INSERT INTO ' . $this->table . '
			SET
				playername = :playername,
				clubname = :clubname,
				gender = :gender,
				dob = :dob,
				ageGroupId = :ageGroupId,
				weightCategoryId = :weightCategoryId';

			// Prepare statement
			$stmt = $this->conn->prepare($query);

			// Clean data
			$this->playername = htmlspecialchars(strip_tags($this->playername));
			$this->clubname = htmlspecialchars(strip_tags($this->clubname));
			$this->gender = htmlspecialchars(strip_tags($this->gender));
			$this->dob = htmlspecialchars(strip_tags($this->dob));
			$this->ageGroupId = htmlspecialchars(strip_tags($this->ageGroupId));
			$this->weightCategoryId = htmlspecialchars(strip_tags($this->weightCategoryId));

			// Bind data
			$stmt->bindParam(':playername', $this->playername);
			$stmt->bindParam(':clubname', $this->clubname);
			$stmt->bindParam(':gender', $this->gender);
			$stmt->bindParam(':dob', $this->dob);
			$stmt->bindParam(':ageGroupId', $this->ageGroupId);
			$stmt->bindParam(':weightCategoryId', $this->weightCategoryId);
			
			// Execute query
			if($stmt->execute()){
				return true;
			}
			
			// Print error if something goes wrong
			printf("ERROR: %s.\n", $stmt->error);
			return false;

		}

	}