Lack of important details for add command

[simbayippy]

There is a lack of the crucial detail where:

the unique identifier for a student is his/her student number, this was not referenced in the UG, telling the readers so would allow them to understand such a case. One may think that its the student name which is the unique identifer

[nus-pe-bot]

Your response not required for this bug as the team has accepted the bug as it is.