如何按类别自定义ggplot中的配色方案？

install.packages("ggplot2")
library(ggplot2)

data <- data.frame(category = c("A", "B", "C", "D"),
                   value = c(10, 20, 15, 25))

my_colors <- c("#FF0000", "#00FF00", "#0000FF", "#FFFF00")

plot <- ggplot(data, aes(x = category, y = value))

plot <- plot + geom_bar(stat = "identity", fill = my_colors)

plot <- plot + labs(title = "Custom Color Scheme",
                    x = "Category",
                    y = "Value")

print(plot)