Merge branch 'bugfix/wikipage' into dev

core/src/main/java/de/srsoftware/umbrella/core/model/WikiPage.java

@@ -18,7 +18,7 @@ public class WikiPage implements Mappable {
 	private final long id;
 	private String title;
 	private int version;
-	private final List<Integer> versions = new ArrayList<>();
+	private final Set<Integer> versions = new TreeSet<>();
 	private final Map<Long,Member> members = new HashMap<>();
 	private String content;
 	private Set<String> dirtyFields = new HashSet<>();
@@ -157,7 +157,7 @@ public class WikiPage implements Mappable {
 		return version;
 	}
 
-	public List<Integer> versions(){
+	public Set<Integer> versions(){
 		return versions;
 	}
 }