devtools::load_all("~/packages/ggplot2")
#> ℹ Loading ggplot2

data = tibble(
  x = factor(c('a', 'a', 'a', 'a', 'b', 'b', 'b', 'b')),
  group = factor(c('c', 'd', 'c', 'd', 'c', 'd', 'c', 'd')),
  lower = seq(0, 3, length.out = 8),
  middle = seq(1, 4, length.out = 8),
  upper = seq(2, 5, length.out = 8)
)

ggplot(data, aes(x = x, y = middle, color = group)) +
  geom_errorbar(
    aes(ymin = lower, ymax = upper),
    position = position_jitterdodge(dodge.width = 0.75, seed = 1)
  )