fix(curriculum): clarify exercise tracker

curriculum/challenges/english/05-apis-and-microservices/apis-and-microservices-projects/exercise-tracker.md

@@ -16,6 +16,48 @@ Build a full stack JavaScript app that is functionally similar to this: <https:/
 
 When you are done, make sure a working demo of your project is hosted somewhere public. Then submit the URL to it in the `Solution Link` field. Optionally, also submit a link to your project's source code in the `GitHub Link` field.
 
+# --instructions--
+
+Your responses should have the following structures.
+
+Exercise:
+
+```js
+{
+  username: "fcc_test"
+  description: "test",
+  duration: 60,
+  date: "Mon Jan 01 1990",
+  _id: "5fb5853f734231456ccb3b05"
+}
+```
+
+User:
+
+```js
+{
+  username: "fcc_test",
+  _id: "5fb5853f734231456ccb3b05"
+}
+```
+
+Log:
+
+```js
+{
+  username: "fcc_test",
+  count: 1,
+  _id: "5fd01a41c5b5cf05d080502f",
+  log: [{
+    description: "test",
+    duration: 60,
+    date: "Mon Jan 01 1990",
+  }]
+}
+```
+
+**Hint:** For the `date` property, the `toDateString` method of the `Date` API can be used to achieve the expected output.
+
 # --hints--
 
 You should provide your own project, not the example URL.