adds similar helper method recommendations for the Goal model

Author: anselrognlie

ada-project-docs/wave_05.md

@@ -68,6 +68,10 @@ and get this response:
 
 so that I know I successfully created a goal that is saved in the database.
 
+Similar to the Task model, we could add a class method to the Goal model that initializes a new instance from a dictionary, and use this method in the route. If all of our models have this method, we could create a route helper method that initializes a new model instance from a dictionary, and use it in this route and any other route that creates a new model instance.
+
+Also like the Task model, notice that the data nested under the `"goal"` key is a dictionary representation of the goal that was created. Creating a model helper method to return this dictionary, which we can then use to help build this route response, will improve the consistency of our endpoints.
+
 ### Get Goals: Getting Saved Goals
 
 As a client, I want to be able to make a `GET` request to `/goals` when there is at least one saved goal and get this response:
@@ -87,6 +91,8 @@ As a client, I want to be able to make a `GET` request to `/goals` when there is
 ]
 ```
 
+Notice that each data item in the list is a dictionary representation of a goal. Creating a model helper method to return this dictionary, which we can then use to help build this route response, will improve the consistency of our endpoints.
+
 ### Get Goals: No Saved Goals
 
 As a client, I want to be able to make a `GET` request to `/goals` when there are zero saved goals and get this response:
@@ -112,6 +118,10 @@ As a client, I want to be able to make a `GET` request to `/goals/1` when there
 }
 ```
 
+Notice that the data nested under the `"goal"` key is a dictionary representation of the goal that was retrieved. Creating a model helper method to return this dictionary, which we can then use to help build this route response, will improve the consistency of our endpoints.
+
+Further, we should remember that retrieving a model by its ID is a common operation. We should consider creating a route helper method that can retrieve a model by its ID, and use it in this route. This method would be very similar in functionality to retrieving a Task model by its ID, so rather than making an entirely new route helper method, we could generalize any similar Task model method to work also work with a Goal (or any other model).
+
 
 ### Update Goal
 
@@ -129,6 +139,8 @@ and get this response:
 
 The response should have a mimetype of "application/json" to keep our API response type consistent.
 
+We should remember that retrieving a model by its ID is a common operation. We should consider creating a route helper method that can retrieve a model by its ID, and use it in this route. This method could be written to work for Goal models, Task models, or any other model.
+
 ### Delete Goal: Deleting a Goal
 
 As a client, I want to be able to make a `DELETE` request to `/goals/1` when there is at least one saved goal and get this response:
@@ -137,6 +149,8 @@ As a client, I want to be able to make a `DELETE` request to `/goals/1` when the
 
 The response should have a mimetype of "application/json" to keep our API response type consistent.
 
+We should remember that retrieving a model by its ID is a common operation. We should consider creating a route helper method that can retrieve a model by its ID, and use it in this route. This method could be written to work for Goal models, Task models, or any other model.
+
 ### No matching Goal: Get, Update, and Delete
 
 As a client, if I make any of the following requests:
@@ -151,7 +165,9 @@ The response code should be `404`.
 
 You may choose the response body.
 
- Make sure to complete the tests for non-existing tasks to check that the correct response body is returned.
+Make sure to complete the tests for non-existing tasks to check that the correct response body is returned.
+
+By using a helper method to retrieve a model by its ID, we could ensure that the response for a non-existing model is consistent across all these routes.
 
 ### Create a Goal: Invalid Goal With Missing Title