var users = 10;
var needed = 5;

var already_picked = [];

for(var i = 0;i<needed;i++){
    var pushed = false;
    do {
        var x = Math.floor(Math.random()*users);
        if(already_picked.indexOf(x)===-1){
            already_picked.push(x);
            console.log(x);
            pushed = true;
        }
    } while (pushed == false);

    
}