Data model mapping: Mark all ID fields @GeneratedValue, make boxed.

 - Marks all SERIAL columns with @GeneratedValue.
 - Makes all SERIAL columns type Integer instead of type int.  This
   enables Hibernate to autogenerate values on insert.

Change-Id: I826d3a58e065c3dd3fa5f588a23226dfe954fb7d
diff --git a/src/main/java/eu/mulk/mulkcms2/cms/users/User.java b/src/main/java/eu/mulk/mulkcms2/cms/users/User.java
index 41e252c..929bc67 100644
--- a/src/main/java/eu/mulk/mulkcms2/cms/users/User.java
+++ b/src/main/java/eu/mulk/mulkcms2/cms/users/User.java
@@ -7,6 +7,8 @@
 import javax.persistence.Column;
 import javax.persistence.Entity;
 import javax.persistence.FetchType;
+import javax.persistence.GeneratedValue;
+import javax.persistence.GenerationType;
 import javax.persistence.Id;
 import javax.persistence.OneToMany;
 import javax.persistence.Table;
@@ -16,8 +18,9 @@
 public class User extends PanacheEntityBase {
 
   @Id
+  @GeneratedValue(strategy = GenerationType.IDENTITY)
   @Column(name = "id", nullable = false)
-  public int id;
+  public Integer id;
 
   @Column(name = "name", nullable = true, length = -1)
   public String name;