order fill in ggplott2 after reorder x : I reordered my plot in ggplott2:

    KR %>% ggplot(aes(x= reorder(categories, -n), n, fill = categories, order = 
    categories)) + geom_bar(stat = "identity") + (axis.title.x=element_blank(), 
    axis.text.x=element_blank(), axis.ticks.x=element_blank()) 

Now I want, that `fill` has the same order as `x`. I tried it with `order` but it doesn't work. 

    str(KR)
    Classes ‘tbl_df’, ‘tbl’ and 'data.frame':	20 obs. of  2 variables:
    $ categories: chr  "Food" "Nightlife" "Bars" "American (Traditional)" ...
    $ n         : int  8576 6334 6067 5312 5250 5229 5220 4118 3868 3673 ...