Updated use cases.

Use cases are currently incomplete.

Updated use cases based on current functionalities.

docs/DeveloperGuide.md

@@ -321,32 +321,26 @@ Priorities: High (must have) - `* * *`, Medium (nice to have) - `* *`, Low (unli
 
 ### Use cases
 
-(For all use cases below, the **System** is the `AddressBook` and the **Actor** is the `user`, unless specified otherwise)
+(For all use cases below, the **System** is `TutorTrack` and the **Actor** is the `Tutor`, unless specified otherwise)
 
-**Use case: Delete a person**
+**Use case: UC01 Add a student**
 
 **MSS**
 
-1.  User requests to list persons
-2.  AddressBook shows a list of persons
-3.  User requests to delete a specific person in the list
-4.  AddressBook deletes the person
+1. User enters command to add a specific student in the list
+2. System adds the student
 
     Use case ends.
 
 **Extensions**
 
-* 2a. The list is empty.
+* 1a. The given syntax is incorrect.
 
-  Use case ends.
+  * 1a1. AddressBook shows an error message.
 
-* 3a. The given index is invalid.
+  Use case resumes at step 1.
 
-    * 3a1. AddressBook shows an error message.
 
-      Use case resumes at step 2.
-
-*{More to be added}*
 
 ### Non-Functional Requirements