feat: add 'Permission Management' guide

Signed-off-by: ItsNeil17 <neil@willofsteel.me>

Author: ItsNeil17

content/docs/en/guides/plugin/permission-management.mdx

@@ -0,0 +1,44 @@
+---
+title: "Permission Management"
+description: "Learn how to manage permission nodes in your Hytale plugin."
+authors:
+    - name: "Neil Revin"
+      link: "https://itsneil.dev"
+    - name: "Bird"
+      link: "https://discord.com/users/495709580068651009"
+---
+
+In this guide, you'll learn how to manage permission nodes in your Hytale plugin.
+
+## The `PermissionsModule` class
+
+The `PermissionsModule` class is responsible for managing permission nodes in your plugin. It provides methods to check, grant and revoke permissions for players.
+
+### Adding Permission Nodes
+
+You need a `Set<String>` containing all the permission nodes you want to add, these are added on top of the already existing permission nodes the user may have, it is not a replacement.
+
+```java
+Set<String> permissions = new HashSet<>();
+PermissionsModule perms = PermissionsModule.get();
+perms.addUserPermission(playerUUID, permissions);
+```
+
+### Removing Permission Nodes
+
+Same as above, we just use the `removeUserPermission` method instead to remove permission nodes.
+
+```java
+Set<String> permissions = new HashSet<>();
+PermissionsModule perms = PermissionsModule.get();
+perms.removeUserPermission(playerUUID, permissions);
+```
+
+### Check Permission Nodes
+
+To check if a player has a specific permission node, you can use the `hasPermission` method.
+
+```java
+PermissionsModule perms = PermissionsModule.get();
+boolean hasPermission = perms.hasPermission(playerUUID, "permission.node");
+```