Making an application live majorly depends on the type of hosting you are having along with the method to access you are provided for that hosting.
There are a number of MySQL client but so far phpmyadmin is one of the popular MySQL client used. It's simple to use, effective and provide almost all the required features for day to day development.
Although the authentication component of CakePHP 3 has made the life of a developer much easier but still there are some functionalities that are still needed to be done manually. One of them is login automatically if the users have checked for 'remember me'.