Use global connection variable, instead of local

app/repositories/orient_db/learning_object_repository.rb

@@ -23,15 +23,15 @@ module OrientDb
     private
 
     def find_by_id(rid)
-      connection.query "SELECT FROM User WHERE @rid=#{rid}"
+      @connection.query "SELECT FROM User WHERE @rid=#{rid}"
     end
 
     def author_of(rid)
-      connection.query "SELECT expand(in) FROM (SELECT expand(out_author_of) FROM User WHERE @rid=#{rid})"
+      @connection.query "SELECT expand(in) FROM (SELECT expand(out_author_of) FROM User WHERE @rid=#{rid})"
     end
 
     def has(rid)
-      connection.query "SELECT expand(in) FROM (SELECT expand(out_has) FROM User WHERE @rid=#{rid})"
+      @connection.query "SELECT expand(in) FROM (SELECT expand(out_has) FROM User WHERE @rid=#{rid})"
     end
 
   end