Online Leaderboard, achievements,upgrades(not on local storage)

I want to create an online leaderboard, some achievements and i want that the player can make some upgrades and all of these things shouldn't be saved on local storage but somewhere else, i wanted to know what is the best way for do these things(with some example if is possible). I wanted also to know how to make the user login at his google play account the first time he open the game.

Use the Google play plugin ,make a login button and on click > sign in.

For a online leader board you need a website, server or a database with the scores, use AJAX to get and post files to browser , you can also use the browser event tof save and load filea.

As I said instead of local try the AJAX plugin , I'm not that good at it so I can't explain much more but I know what your looking for is possible don't give up !

Edit :I also think Google play has leader board but you need to be a customer and purchase dev membership to add apps on Google play