Please do. This is your code so you get to decide exactly how free you want it to be, but without a license, it's "source available" which means that people can't do more than look at it and say "that's nice". If you want to let other people actually do something with it, then it needs a license. I can't decide for you which one to choose, but MIT is popular, let's other people take your code as long as they say where it came from. For web projects that you want to remain free, AGPL is a license that says you can use this code, but any changes you make to it also have to be free. It's a tricky topic that this comment is far too short to cover, but it's worth a hour or two of your time to consider as what you think of as okay to with your source won't align with what everyone else might consider to do with your source.