Extend existing array option overwriting values in array

[EricLarson2020]

Please see the failing spec here: #15

[magynhard]

As you found out (#15) it is a issue or missing feature of the underlying deep_merge gem, i close this related issue as well.

Maybe one of the options of deep_merge fits your desire or a feature request or even a pull request with a solution there might be necessary.

https://github.com/danielsdeleo/deep_merge

Thank you!