Implement edit user modal

EditUserHandler is a bit rough

less/forum/EditUserModal.less

@@ -0,0 +1,9 @@
+.EditUserModal-groups {
+  .checkbox {
+    margin-bottom: 10px;
+  }
+  .Badge {
+    margin: -3px 3px -3px 0;
+    vertical-align: 1px;
+  }
+}

less/forum/app.less

@@ -7,6 +7,7 @@
 @import "DiscussionList.less";
 @import "DiscussionListItem.less";
 @import "DiscussionPage.less";
+@import "EditUserModal.less";
 @import "Hero.less";
 @import "IndexPage.less";
 @import "LogInModal.less";