Add an open source license to the project

[KevBelisle]

There being no license means it is closed-source and no one can use your source code or contribute to it.

[iTrooz]

+1
If you are not sure, the Apache 2.0 licence is a simple licence that should work out for you
Here is what happens if you don't choose a licence: https://choosealicense.com/no-permission/