Add command according to UserGuide is not working

[nus-se-bot]

Describe the bug
The example command in add n/John Doe p/98765432 e/johnd@example.com a/John street, block 123, #1-01
does not work

To Reproduce
Steps to reproduce the behavior:

1. Launched the jar file
2. entered "add n/John Doe p/98765432 e/johnd@example.com a/John street, block 123, Update README #1-01" as according to user guide
3. "Unknown command" message was given

Expected behavior
By UserGuide, A contact named John Doe should be added

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Reported by: @andrewscw
Severity: Medium

_{[original: nus-cs2103-AY1819S2/pe-dry-run#92]}