Created button in menu to open/change the dataset

src/main/java/seng202/group9/GUI/MenuController.java

@@ -114,4 +114,8 @@ public class MenuController extends Controller{
 		}
 	}
 
+	public void openDataset(){
+		createPopUpStage(SceneCode.DATASET_CONTROLLER, 600, 400);
+	}
+	
 }

src/main/resources/menu.fxml

@@ -15,6 +15,8 @@
         <menus>
           <Menu mnemonicParsing="false" text="File">
             <items>
+                  <MenuItem mnemonicParsing="false" onAction="#openDataset" text="New/Open Dataset" />
+                  <SeparatorMenuItem mnemonicParsing="false" />
                   <MenuItem mnemonicParsing="false" onAction="#importAirports" text="Import Airports" />
                   <MenuItem mnemonicParsing="false" onAction="#importAirlines" text="Import Airlines" />
                   <MenuItem mnemonicParsing="false" onAction="#importRoutes" text="Import Routes" />