Track Discord users from documents

CONTRIBUTING.md

@@ -19,7 +19,7 @@ for purposes in the *Libplanet* category:
     Ask questions to *hack* Libplanet and to make a patch for it.  People here
     usually speak in Korean, but feel free to speak in English.
 
-[Discord server]: https://planetarium.dev/discord
+[Discord server]: https://link.planetarium.dev/libplanet-contributing--pl-dev-discord
 
 
 Prerequisites

README.md

@@ -30,7 +30,7 @@ It has competitive advantages over other solutions for decentralized gaming:
 To learn more about why Planetarium is creating technology for fully
 decentralized games, please refer to our [blog post].
 
-[Discord]: https://planetarium.dev/discord
+[Discord]: https://link.planetarium.dev/libplanet-readme--pl-dev-discord
 [CircleCI]: https://app.circleci.com/pipelines/github/planetarium/libplanet
 [Codecov]: https://codecov.io/gh/planetarium/libplanet
 [NuGet]: https://www.nuget.org/packages/Libplanet/

tools/Libplanet.Explorer/README.md

@@ -28,7 +28,7 @@ store blockchain instead of storage.
 
 [.NET Core]: https://dotnet.microsoft.com/
 [PowerShell]: https://microsoft.com/PowerShell
-[1]: https://planetarium.dev/discord
+[1]: https://link.planetarium.dev/libplanet-explorer-readme--pl-dev-discord
 
 
 GraphQL