KB66 Add comment box.

Change-Id: I9bf140ded85045b09997145ed2a9fb421fedc7d4
diff --git a/src/main/java/eu/mulk/mulkcms2/benki/posts/Post.java b/src/main/java/eu/mulk/mulkcms2/benki/posts/Post.java
index 2c56285..d3e7712 100644
--- a/src/main/java/eu/mulk/mulkcms2/benki/posts/Post.java
+++ b/src/main/java/eu/mulk/mulkcms2/benki/posts/Post.java
@@ -109,6 +109,10 @@
   @JsonbTransient
   public Set<Role> targets;
 
+  @ManyToMany(mappedBy = "referees")
+  @JsonbTransient
+  public Collection<LazychatMessage> referrers;
+
   @OneToMany(
       mappedBy = "post",
       fetch = FetchType.LAZY,
@@ -389,6 +393,16 @@
     }
   }
 
+  public Collection<LazychatMessage> getComments() {
+    return referrers.stream()
+        .filter(l -> l.scope == Scope.comment)
+        .sorted(
+            Comparator.comparing(
+                    (LazychatMessage l) -> Objects.requireNonNullElse(l.date, OffsetDateTime.MIN))
+                .reversed())
+        .toList();
+  }
+
   public enum Visibility {
     PUBLIC,
     SEMIPRIVATE,