Add database module draft

shell.nix

@@ -3,9 +3,11 @@
 with pkgs;
 
 mkShell {
-  buildInputs = [ php mysql57 ];
+  buildInputs =
+    [ php74 php74Extensions.pdo_mysql php74Packages.composer mysql57 ];
 
   shellHook = ''
+    pkill mysql
     rm -rf .mysql && mkdir .mysql
 
     mysqld --datadir="$(pwd)/.mysql" --socket="$(pwd)/.mysql/mysql.sock" --initialize-insecure

src/database.php

@@ -0,0 +1,13 @@
+<?php
+
+function connectDatabase($user, $pass, $db) {
+    $unix_socket = '.mysql/mysql.sock';
+    $charset = 'utf8mb4';
+    $dsn = "mysql:unix_socket=$unix_socket;dbname=$db;charset=$charset";
+    $db_connection = new PDO($dsn, $user, $pass);
+    return $db_connection;
+}
+
+function closeDatabase($db_connection) {
+    $db_connection = null;
+}