macOS fails to start the executable when installed manually

Yesterday in the gitter, there was a screenshot posted of a user doing the manual installation, the message apeared everytime they ran `exercism` on the terminal:


Googling the error lead me to an issue in the terraform issue tracker:

hashicorp/terraform#23033

Throughout the issue some suggestions and workarounds.

I do not use macOS, therefore I can't verify, nor do I understand all of the stuff in the issue, but it seems that there are a couple of "workarounds" and "fixes" that might work or might not work, depending on the version of macOS, also some might put the system under severe risks, like disabling this check globally.

Though what would work is to "sign" the binary such that macOS considers it a legitimate one.

Therefore I propose to either add an additional section to the manual installation path, that checks and solves the symptoms described in this post, or that the exercism.io team should try to get a signing key to properly distribute signed binaries.