fix: update CONTRIBUTING.md to reference Discord instead of Gitter

Updated contact information for questions about the repository.

Author: prasanth-30011

CONTRIBUTING.md

@@ -26,6 +26,5 @@ NOTE: *Please avoid opening issues asking to be "assigned" to a particular algor
 
 ### Do you have questions about the source code?
 
-- Ask any question about how to use the repository in the [TheAlgorithms room in GITTER](https://gitter.im/TheAlgorithms/community?source=orgpage#) or [open a new issue](https://github.com/TheAlgorithms/Java/issues/new)
-
-:+1::tada: That's all you need to know about the process now it's your turn to help us improve the repository, thank you again! :+1::tada:
+- Ask any question about how to use the repository in the [TheAlgorithms Discord](https://discord.gg/c7F54C89) or [open a new issue](https://github.com/TheAlgorithms/Java/issues/new)
+:+1::tada: That's all you need to know about the process now it's your turn to help us improve the repository, thank you again! :+1::tada: