update test and add solution for DS challenge closed #164

[HugoLiconV]

Description

I added the solutions for «Data Structures: Add a New Element to a Binary Search Tree» challenge and I also modified one test to fix issue #164

Pre-Submission Checklist

• Your pull request targets the dev branch.
• Branch starts with either fix/, feature/, or translate/ (e.g. fix/challenge-tests)
• All new and existing tests pass the command npm test.
• [] Use npm run commit to generate a conventional commit message.
  Learn more here: https://conventionalcommits.org/#why-use-conventional-commits
• The changes were done locally on your machine and NOT GitHub web interface.
  If they were done on the web interface you have ensured that you are creating conventional commit messages.

Checklist:

• Tested changes locally.
• Addressed currently open issue (replace XXXXX with an issue no in next line)

Closes #XXXXX

[scissorsneedfoodtoo]

Thank you for taking the time to submit this PR, @HugoLiconV. Unfortunately it seems like the Travis CI build is failing because you don't have a conventional commit message.

Please take a look at our Contributor's Guide for more information about generating a conventional commit message and updating your pull request so we can merge it. Also, feel free to reach out to us in the comments here or in the Contributor's Chatroom if you need any assistance.