Updated javadoc..

core/nb-configuration.xml

@@ -37,6 +37,7 @@ Without this configuration present, some functionality in the IDE may be limited
         <word>sitemap</word>
         <word>struct</word>
         <word>structs</word>
+        <word>Swithches</word>
         <word>Upgrader</word>
         <word>Upgraders</word>
     </spellchecker-wordlist>

core/src/main/java/org/b3log/solo/service/UserMgmtService.java

@@ -114,10 +114,11 @@ public final class UserMgmtService {
     }
 
     /**
-     * change user role by the specified userid.
+     * Swithches the user role between "defaultRole" and "visitorRole"  by the specified user id.
      *
-     * @param userId the specified userid
+     * @param userId the specified user id
      * @throws ServiceException exception
+     * @see User
      */
     public void changeRole(final String userId) throws ServiceException {
         final Transaction transaction = userRepository.beginTransaction();