code: public SortableBehavior setGrid(int x, int y)
  	{
  		ArrayItemOptions<IntegerItemOptions> grids = new ArrayItemOptions<IntegerItemOptions>();
  		grids.add(new IntegerItemOptions(x));
  		grids.add(new IntegerItemOptions(y));
  		this.options.put("grid", grids);
  		return this;
  	}
docs: Snaps the sorting element or helper to a grid, every x and y pixels. Array values:
  [x, y]
  
  @param x
  @param y
  @return instance of the current behavior