update readme with a step for writing tests

Author: derekeder

README.md

@@ -53,19 +53,29 @@ This way you go about completing these goals is meant to be open-ended, so tackl
 
 In `map/serializers.py`, supplement each community area with data on the amount of permits issued in each area during the currently filtered year. From here, the view will pass that data to the front end.
 
-### Step 2: Filter results by a specific year
+### Step 2: Write a test for your data endpoint
+
+In `tests/test_views.py` implement a test to validate the data that your endpoint produces. You will want to create some test `CommunityArea` and `RestaurantPermit` objects and then assert that the expected values are returned when querying the endpoint.
+
+Use this command to run tests:
+
+```bash
+ docker compose -f docker-compose.yml -f tests/docker-compose.yml run --rm app
+```
+
+### Step 3: Filter results by a specific year
 
 In `map/static/js/RestaurantPermitMap.js`, create a filter that allows users to send a request for a specific year to the backend. The options shoulds be any year between 2016 and 2026, inclusive. Then, use the fetch api in the map component to make a request and receive that data.
 
-### Step 3: Display results on the page
+### Step 4: Display results on the page
 
 In the map component, process the community area and use it to display shapes for all areas on the map. Then, display the total number of restaurant permits that year as well as the maximum number of permits in any one area.
 
-### Step 4: Make the map dynamic
+### Step 5: Make the map dynamic
 
 Start displaying some data! Use the `setAreaInteraction()` method to shade the map according to how many permits it has in a year, making sure that it updates automatically when a new year is selected. In this same method, have each area display a popup during some kind of user interaction. The popup should have some light details to help the user understand what they're looking at.
 
-### Step 5: Submit your work
+### Step 6: Submit your work
 
 To submit your work, create a feature branch for your code, commit your changes, push your commits up to your fork, and open up a pull request against main. Finally, drop a link to your pull request in your application.