How do you grow a community?

Hello! I'm the founder of www.trybutlerapp.com

When I introduce our mobile app to someone in person and have the chance to walk people through it I've heard "Wow, I can't wait until that's totally finished." or "oh, I've always needed this."

But I'm having a hard time cultivating that same reaction online. Butler is a curated search engine for media, a tool to best use your leisure time, and a way to never forget or lose a recommendation again. Streaming is becoming more popular than ever and every service is disjointed. Butler is a really quick tool to use to save that movie or tv show to watch later, learn where it's streaming, who's in it, and find more recommendations.

I've started tweeting more about this https://twitter.com/Zeitzew32 and we have a discord server that users on our app can join to share feature requests (or bugs). I'd love to learn how you grew your communities online for your products and ways that I can best move forward. How did you get your first Twitter following or discord users?