add bookdown import and tidy up rmd
diff --git a/R/posterdown.R b/R/posterdown.R
index fd1e995..ea111c6 100644
--- a/R/posterdown.R
+++ b/R/posterdown.R
@@ -9,6 +9,7 @@
 #' @docType package
 #' @name posterdown
 #' @import rmarkdown
+#' @import bookdown
 #' @import ggplot2
 #' @import knitr
 NULL