custom auth and hashing laravel 5.1

I have an existing database.

users :
username => varchar
password => md5 hashing

I am new to laravel, I was try to create simple login and register from laravel docs, thats work fine, but in docs are create for laravel, now I want to create same login/register but with existing datas.

I was read some Question from How to use SHA1 encryption instead of BCrypt in Laravel 4? but I dont understand how to use it.

any adv?

sory for my bad grammer.

via Chebli Mohamed