Prevent multiple submissions of create/update form

[codecov[bot]]

Codecov Report

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

Project coverage is 91.10%. Comparing base (a9e2e7c) to head (64570e5). Report is 6 commits behind head on master.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #309 +/- ## ======================================= Coverage 91.10% 91.10% ======================================= Files 32 32 Lines 2406 2406 ======================================= Hits 2192 2192 Misses 214 214 ```

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