Insert pull-right into the class attribute and let bootstrap arrange the buttons.
For Bootstrap 2.3, see: http://getbootstrap.com/2.3.2/components.html#misc > Helper classes > .pull-right.
For Bootstrap 3, see: https://getbootstrap.com/docs/3.3/css/#helper-classes > Helper classes.
For Bootstrap 4, see: https://getbootstrap.com/docs/4.0/utilities/float/#responsive
The pull-right command was removed and replaced with float-right or in general to float-{sm,md,lg,xl}-{left,right,none}