Allow Reloading of Custom Permissions

https://github.com/PaperMC/Paper/issues/49

paper-server/src/main/java/org/bukkit/craftbukkit/CraftServer.java

@@ -2818,5 +2818,23 @@ public final class CraftServer implements Server {
         }
         return this.adventure$audiences;
     }
+
+    @Override
+    public void reloadPermissions() {
+        pluginManager.clearPermissions();
+        if (io.papermc.paper.configuration.GlobalConfiguration.get().misc.loadPermissionsYmlBeforePlugins) loadCustomPermissions();
+        for (Plugin plugin : pluginManager.getPlugins()) {
+            for (Permission perm : plugin.getDescription().getPermissions()) {
+                try {
+                    pluginManager.addPermission(perm);
+                } catch (IllegalArgumentException ex) {
+                    getLogger().log(Level.WARNING, "Plugin " + plugin.getDescription().getFullName() + " tried to register permission '" + perm.getName() + "' but it's already registered", ex);
+                }
+            }
+        }
+        if (!io.papermc.paper.configuration.GlobalConfiguration.get().misc.loadPermissionsYmlBeforePlugins) loadCustomPermissions();
+        DefaultPermissions.registerCorePermissions();
+        CraftDefaultPermissions.registerCorePermissions();
+    }
     // Paper end
 }