link label to mindmaps

wise-webapp/src/main/java/com/wisemapping/model/Mindmap.java

@@ -44,6 +44,7 @@ public class Mindmap {
     private User lastEditor;
 
     private Set<Collaboration> collaborations = new HashSet<Collaboration>();
+    private Set<Label> labels = new HashSet<Label>();
 
     private User creator;
     private String tags;
@@ -118,6 +119,18 @@ public class Mindmap {
         collaborations.add(collaboration);
     }
 
+    @NotNull public Set<Label> getLabels() {
+        return labels;
+    }
+
+    public void setLabels(@NotNull final Set<Label> labels) {
+        this.labels = labels;
+    }
+
+    public void addLabel(@NotNull final Label label) {
+        this.labels.add(label);
+    }
+
     @Nullable
     public Collaboration findCollaboration(@NotNull Collaborator collaborator) {
         Collaboration result = null;