Added methods to get logged-in user ID

Added methods to get logged-in user ID based on user's username that was used at log-in.
Signed-off-by: Bruno Nocera Zanette <brunonzanette@gmail.com>

src/main/java/br/ufpr/c3sl/sapos/models/util/KerberosAuthProvider.java

 package br.ufpr.c3sl.sapos.models.util;
 
+import br.ufpr.c3sl.sapos.models.scholar.Registration;
 import br.ufpr.c3sl.sapos.models.util.LdapAttrProvider;
 
 import java.util.Collection;
@@ -45,6 +46,19 @@ public class KerberosAuthProvider implements UserDetailsService {
 	public static Collection<? extends GrantedAuthority> authAluno = AuthorityUtils
 			.createAuthorityList("Aluno");
 	
+	public static String getIdFromLoggedInStudent(){
+		return Registration.entityManager().createNativeQuery(
+				"SELECT r.id from registration r, person p"+
+				" WHERE r.student = p.id"+
+				" and p.user_name ="+"'"+getPersonUsername()+"'").getSingleResult().toString();
+	}
+	
+	public static String getIdFromLoggedInProfessor(){
+		return Registration.entityManager().createNativeQuery(
+				"SELECT p.id from person p"+
+				" WHERE p.user_name ="+"'"+getPersonUsername()+"'").getSingleResult().toString();
+	}
+	
 	// This method is used to remove the suffix added by Kerberos
 	// By Kerberos's definition: krbPrincipalName = Username@Server
 	private static String removeKrbSuffix(String username){