move edge methods from learning object repository to edge methods module

app/repositories/orient_db/learning_object_repository.rb

@@ -49,13 +49,6 @@ module OrientDb
       edges.flatten
     end
 
-    # Usage:
-    #   repository.for(:learning_objects).destroy learning_object
-    #
-    def destroy(learning_object)
-      connection.command sprintf("DELETE VERTEX #{odb_class} where @rid = '%s'", learning_object.id)
-    end
-
     ##
     # To create "index:learningobject_search" on OrientDB, use the following command:
     #   CREATE INDEX learningobject_search
@@ -102,16 +95,6 @@ module OrientDb
 
     private
 
-    def create_edges_from_array(edge_class, id, array, unique=false)
-      edges = []
-      array.each do |o|
-        unless unique && edge_exists?(edge_class, id, o.id)
-          edges << create_edge(edge_class, id, o.id)
-        end
-      end
-      edges
-    end
-
     def odb_class
       "LearningObject"
     end

lib/orient_db/methods/edge_methods.rb

@@ -2,6 +2,16 @@ module OrientDb
   module Methods
     module EdgeMethods
 
+      def create_edges_from_array(edge_class, id, array, unique=false)
+        edges = []
+        array.each do |o|
+          unless unique && edge_exists?(edge_class, id, o.id)
+            edges << create_edge(edge_class, id, o.id)
+          end
+        end
+        edges
+      end
+
       ##
       # Count the number of edges existent
       def get_in_edges_count(edge_class, id)