Add GlitchTip to list

[jamesrkiger]

Hello. I was hoping to add the open-source project I work on to this list. Normally we mention Sentry as our primary competitor, but I wanted to ask if this is alright since they also seem to be on this list. Thanks for your time.

[garrrikkotua]

Hey, thanks for your PR!

We are open for all projects, but we decided to put a lower bound on number of stars (100 GitHub / GitLab stars).

I will make a note and add your repo as soon as you reach 100 stars. Hope it makes sense :)