Fatal: /discourse までのマウントポイント上のいずれのディレクトリも git リポジトリではありません

[pfaffman (Jay Pfaffman)]

Are you trying to add the discourse-rating plugin to your production site? Did you try this? Install Plugins in Discourse

Are you trying to change how Discourse works? See Beginner's Guide to Creating Discourse Plugins - Part 1