KB56 PostText: Inherit from PanacheEntityBase.

PostText did not inherit from PanacheEntityBase.  This meant that
automatic setter and getter generation (and thus dirtiness tracking)
was not working, making updates to existing post texts impossible.

Change-Id: I0901b15acc73827276322feb000831a8e93d5717
diff --git a/src/main/java/eu/mulk/mulkcms2/benki/posts/PostText.java b/src/main/java/eu/mulk/mulkcms2/benki/posts/PostText.java
index 01753dc..8b1697c 100644
--- a/src/main/java/eu/mulk/mulkcms2/benki/posts/PostText.java
+++ b/src/main/java/eu/mulk/mulkcms2/benki/posts/PostText.java
@@ -1,5 +1,6 @@
 package eu.mulk.mulkcms2.benki.posts;
 
+import io.quarkus.hibernate.orm.panache.PanacheEntityBase;
 import javax.annotation.CheckForNull;
 import javax.json.bind.annotation.JsonbTransient;
 import javax.persistence.Column;
@@ -17,7 +18,7 @@
 @Table(name = "post_texts", schema = "benki")
 @Inheritance(strategy = InheritanceType.TABLE_PER_CLASS)
 @IdClass(PostTextPK.class)
-public abstract class PostText<OwningPost extends Post<?>> {
+public abstract class PostText<OwningPost extends Post<?>> extends PanacheEntityBase {
 
   private static final int DESCRIPTION_CACHE_VERSION = 1;