Add use cases

docs/DeveloperGuide.md

@@ -316,32 +316,46 @@ 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)
-
-**Use case: Delete a person**
+(For all use cases below, the **System** is `AssetBook-3 (AB3)` and the **Actor** is the `user`, unless specified otherwise)
 
+**Use case: UC1 - Add a contact**
 **MSS**
+1. User requests to add a contact.
+2. User specifies details of the contact.
+3. AB3 adds the contact.
 
-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
+Use case ends.
 
-    Use case ends.
 
-**Extensions**
+**Use case: UC2 - Add an asset**
+**MSS**
+1. User requests to add an asset.
+2. User specifies details of the asset.
+3. AB3 adds the asset.
 
-* 2a. The list is empty.
+Use case ends.
 
-  Use case ends.
 
-* 3a. The given index is invalid.
+**Use case: UC3 - Assign assets to a contact**
+**MSS**
+1. User requests to assign an asset to the contact.
+2. User specifies the contact.
+3. User specifies the asset.
+4. AB3 assigns the asset to the contact.
 
-    * 3a1. AddressBook shows an error message.
+Steps 1-4 are repeated until all the assets are assigned to the contact.
+Use case ends.
 
-      Use case resumes at step 2.
+**Extensions**
+* 2a. Contact was not created.
+    * 2a1. User exits assign request.
+    * 2a2. User creates the contact (UC1).
+    Use case resumes from step 1.
+* 3a. Asset was not created.
+    * 3a1. User exits assign request.
+    * 3a2. User creates the asset (UC2).
+    Use case resumes from step 1.
 
-*{More to be added}*
 
 ### Non-Functional Requirements