Add checkmark to mark all files

src/main/resources/templates/changes.html

@@ -11,7 +11,7 @@
 <form method="post" th:action="@{/repo/{name}/stage(name=${name})}" th:if="${!#lists.isEmpty(modifiedFiles)}">
 <table border="1" cellpadding="4" cellspacing="0">
 <tr>
-<th></th>
+<th><input type="checkbox" name="selectAll"></th>
 <th>File</th>
 </tr>
 <tr th:each="file : ${modifiedFiles}">
@@ -29,7 +29,7 @@
 <form method="post" th:action="@{/repo/{name}/unstage(name=${name})}" th:if="${!#lists.isEmpty(stagedFiles)}">
 <table border="1" cellpadding="4" cellspacing="0">
 <tr>
-<th></th>
+<th><input type="checkbox" name="selectAll"></th>
 <th>File</th>
 </tr>
 <tr th:each="file : ${stagedFiles}">