diff --git a/man/auto_index.Rd b/man/auto_index.Rd
new file mode 100644
index 0000000..abec3be
--- /dev/null
+++ b/man/auto_index.Rd
@@ -0,0 +1,16 @@
+% Generated by roxygen2: do not edit by hand
+% Please edit documentation in R/group_rows.R
+\name{auto_index}
+\alias{auto_index}
+\title{Automatically figuring out the group_row index}
+\usage{
+auto_index(x)
+}
+\arguments{
+\item{x}{The index column. A vector. For example `c("a", "a", "b", "b", "b")``}
+}
+\description{
+This helper function allows users to build the \code{group_row}
+index more quickly and use \code{group_rows} in a way that is similar with
+\code{collapse_rows}.
+}
diff --git a/man/collapse_rows.Rd b/man/collapse_rows.Rd
index 49f9833..3609041 100644
--- a/man/collapse_rows.Rd
+++ b/man/collapse_rows.Rd
@@ -4,8 +4,9 @@
 \alias{collapse_rows}
 \title{Collapse repeated rows to multirow cell}
 \usage{
-collapse_rows(kable_input, columns = NULL, latex_hline = c("full", "major",
-  "none", "custom"), row_group_label_position = c("identity", "stack"),
+collapse_rows(kable_input, columns = NULL, valign = c("top", "middle",
+  "bottom"), latex_hline = c("full", "major", "none", "custom"),
+  row_group_label_position = c("identity", "stack"),
   custom_latex_hline = NULL, row_group_label_fonts = NULL,
   headers_to_remove = NULL)
 }
@@ -14,6 +15,8 @@
 
 \item{columns}{Numeric column positions where rows need to be collapsed.}
 
+\item{valign}{Select from "top"(default), "middle", "bottom"}
+
 \item{latex_hline}{Option controlling the behavior of adding hlines to table.
 Choose from \code{full}, \code{major}, \code{none}, \code{custom}.}