improve documentation

src/main/java/net/hostsharing/hsadminng/hs/office/coopshares/HsOfficeCoopSharesTransactionEntity.java

@@ -59,9 +59,15 @@ public class HsOfficeCoopSharesTransactionEntity implements Stringifyable, HasUu
     @Column(name = "sharecount")
     private int shareCount;
 
+    /**
+     * The ooking reference.
+     */
     @Column(name = "reference")
     private String reference;
 
+    /**
+     * An optional arbitrary comment.
+     */
     @Column(name = "comment")
     private String comment;