Tambah file konfigurasi
	modified:   back-end/config/config.php
	modified:   back-end/config/functions.php
Tambah file koneksi dan pesan flash
	back-end/config/koneksi.php
	back-end/view/content/flash.php
CRUD data pelanggan
Tambah file
- koneksi
- session cek
- session keluar
- session mulai
- pesan flash
- data pelanggan
	back-end/config/koneksi.php
	back-end/config/session_cek.php
	back-end/config/session_keluar.php
	back-end/config/session_mulai.php
	back-end/view/content/flash.php
	back-end/view/content/pelanggan/
Koneksi session