Add descriptions for assign command

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 65.41%. Comparing base (e27de02) to head (8598895). Report is 2 commits behind head on master.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #217 +/- ## ========================================= Coverage 65.41% 65.41% Complexity 566 566 ========================================= Files 95 95 Lines 2212 2212 Branches 226 226 ========================================= Hits 1447 1447 Misses 680 680 Partials 85 85 ```

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