title: How do I add p-values to my ggplot using the geom_signif command?
body: <p>I am trying to add p-values to my ggplot bar plots. I do not want to use the built in significant tests through geom_signif
  I have calculated the p value through t.test and want to add that to my plot.</p>
  <pre><code>anno = t.test(Slc22a18~Treatment, data = Genes, var.equal = T)
  </code></pre>
  <p>Code for my plot is</p>
  <pre><code>Slc22 = ggplot(data = Genes, aes(x = Treatment, y = Slc22a18, fill = Treatment)) +
    geom_bar(stat = 'identity', position = position_dodge(1), width = 0.3) +
   scale_fill_manual(values = c('lightsalmon', 'orangered3')) +
  geom_point() +
  theme_minimal() +
  labs(y = 'Relative Expression') +
  ggtitle('Slc22a18') +
  geom_signif(annotations = anno$p.value)
  </code></pre>
  <p>When I run this code I get this error -</p>
  <pre><code>Warning message:
  Computation failed in `stat_signif()`:
  arguments imply differing number of rows: 0, 3 
  </code></pre>
  <p>When I run the code without geom_signif() it works just fine.</p>