Results 5 issues of Arnau Sanchez

I use `Enumerable#map_by` a lot, it's a great abstraction because, more often than not, `Enumerable#group_by` falls too short. However, there are a couple of closely related problems with its implementation...

bug

This does not work for me (using current master): ``` person.ruby[field2][foo] ``` Note that I use "f" instead of "foo". I get "Uncaught TypeError: Object # has no method 'push'"

This solves #10 for me.

It may be worth adding to the README that we need an extra argument for chromium >= 111: ``` $ google-chrome --remote-debugging-port=9222 --remote-allow-origins=* ```

https://dhis2.atlassian.net/browse/DHIS2-14139 When trying to delete a file (data element of type FILE_RESOURCE) in Tracker Capture, the event PUT request fails with a NullPointerException. Checking if the object is null before...