Push item to associative array in PHP
$options['inputs']['name'] = $new_input['name'];
Instead of array_push(), use array_merge()
It will merge two arrays and combine their items in a single array.
Example Code -
$existing_array = array('a'=>'b', 'b'=>'c');
$new_array = array('d'=>'e', 'f'=>'g');
$final_array=array_merge($existing_array, $new_array);
Its returns the resulting array in the final_array. And results of resulting array will be -
array('a'=>'b', 'b'=>'c','d'=>'e', 'f'=>'g')
Please review this link, to be aware of possible problems.