This is a problem that had me confused for an embarrassingly long time. Rails wraps button_to elements within a form and a div. Unfortunately this will take up 100% of the available width. Thankfully the solution is pretty straight forward – simply wrap buttons in a div and float them left like so:
A wrapper div isn’t strictly necessary however I usually add one just to be safe. While this will probably give a bunch of designers another reason to hate developers, I find that wrapping floated elements seems to save a lot of headaches when making changes down the track.
Using the code above you may also find that the divs aren’t filling as expected, simply add a div with a ‘clear:both’ style to the bottom of the wrapper: