Not so much a recommendation on where to publish, but I do suggest you form relationships and connections with other writers. It may seem like a solitary art form, but you can’t do it alone.

Thy said, the platform doesn’t matter. No one will find your content unless you cultivate an audience. There’s not much difference between Medium and GitHub and pastebin as far as your audience is concerned. If you want readers you’ll need an outlet that has them already (existing magazine, for example) or you’ll have to learn about marketing and promotion.

Good luck. Keep writing! The world needs your stories.