message: Remove patron link and changer gitter links to discord links.
diff: @@ -75,13 +75,12 @@ It walks you through getting a wikipedia search engine up and running in a few m
  There are many ways to support this project.
  -- Use Tantivy and tell us about your experience on [Gitter](https://gitter.im/tantivy-search/tantivy) or by email (paul.masurel@gmail.com)
  +- Use Tantivy and tell us about your experience on [Discord](https://discord.gg/MT27AG5EVE) or by email (paul.masurel@gmail.com)
  - Report bugs
  - Write a blog post
  - Help with documentation by asking questions or submitting PRs
  -- Contribute code (you can join [our Gitter](https://gitter.im/tantivy-search/tantivy))
  +- Contribute code (you can join [our Discord server](https://discord.gg/MT27AG5EVE))
  - Talk about Tantivy around you
  -- [![Become a patron](https://c5.patreon.com/external/logo/become_a_patron_button.png)](https://www.patreon.com/fulmicoton)
  # Contributing code
  