onSubmit(values) {
        // this === component
        this.props.createPost(values, () => {
            this.props.history.push('/');
        });
    }
// called by Redux Form's handleSubmit which calls the validation
called by Redux Form's handleSubmit which calls the validation
called by Redux Form ' s handleSubmit which calls the validation
onSubmit(values) {
        this.props.createPost(values, () => {
            this.props.history.push('/');
        });
    }
onSubmit ( values ) { this . props . createPost ( values , ( ) => { this . props . history . push ( '/' ) ; } ) ; }
called by Redux Form's handleSubmit which calls the validation
called by Redux Form ' s handleSubmit which calls the validation
// this === component