How can I make this piece of code asynchronous via promises ? : 
Any Glue. ***Please do not give example of SETTIMEOUT.***

My supervisor said that it is unnecessary having more then() statement if the then()'s do not return any new promise.I could not get it completely, I have looked at Exploring ES6 but there is no very well example of my situation. 

<!-- begin snippet: js hide: false console: true babel: false -->

<!-- language: lang-js -->



    let readData = new Promise(function (resolve, reject) {
        fs.readFile('/home/geek/Desktop/activity-logs.csv', 'utf8', (err, data) => {
            if (err)
                reject();
            resolve(data);

        });

    });

    readData
        .then((data) => {
            bankLogs = splitString(data, ';')
        })
        .then(() => {
            for (let index = 2; index < bankLogs.length; index += 5) {
                objectOfUsers[bankLogs[index]] = {}
                temporarySymbols.push(bankLogs[index].concat(bankLogs[index + 1]));
            }
            Object.keys(objectOfUsers).forEach(function (element) {
                objectKeys.push(element)
            });
            for (let index = 0; index < objectKeys.length; index++)
                createObject(index);
            console.log(objectOfUsers)
        })
        .catch((err) => console.log('Error happened : ' + err));

<!-- end snippet -->

