Exception when creating a permission group
**Describe the bug**<br>
https://pastes.cf/Yr2teTGV24/


**Steps for reproducing**<br>
1. Type "perms create group NAME 0" into the console
2. See the exception from above in every screen


**Expected behavior**<br>
The group should be created (which it it), but without any errors


**Please provide us information about your environment and used assets**

This shouldn't matter, but:
 System specs: CPU = Intel i7 6700k; DDR 4 2400 MHz 16 GB HyperX RAM; 2 TB Seagate HDD
 OS: Windows 10
 Version: https://github.com/CloudNetService/CloudNet-v3/tree/6530b93faf1eca66d0468ead61036d76b38ffec0

diff --git a/cloudnet/src/main/java/de/dytanic/cloudnet/permission/DefaultDatabasePermissionManagement.java b/cloudnet/src/main/java/de/dytanic/cloudnet/permission/DefaultDatabasePermissionManagement.java
index aa3d73162..f513e6ace 100644
--- a/cloudnet/src/main/java/de/dytanic/cloudnet/permission/DefaultDatabasePermissionManagement.java
+++ b/cloudnet/src/main/java/de/dytanic/cloudnet/permission/DefaultDatabasePermissionManagement.java
@@ -194,11 +194,13 @@ public final class DefaultDatabasePermissionManagement implements IPermissionMan
         Validate.checkNotNull(group);
 
         IPermissionGroup permissionGroup = permissionGroupsMap.remove(group);
-        if (permissionManagementHandler != null) {
-            permissionManagementHandler.handleDeleteGroup(this, permissionGroup);
-        }
+        if (permissionGroup != null) {
+            if (permissionManagementHandler != null) {
+                permissionManagementHandler.handleDeleteGroup(this, permissionGroup);
+            }
 
-        saveGroups();
+            saveGroups();
+        }
     }
 
     @Override
@@ -328,4 +330,4 @@ public final class DefaultDatabasePermissionManagement implements IPermissionMan
     public void setPermissionManagementHandler(IPermissionManagementHandler permissionManagementHandler) {
         this.permissionManagementHandler = permissionManagementHandler;
     }
-}
\\ No newline at end of file
+}
['cloudnet/src/main/java/de/dytanic/cloudnet/permission/DefaultDatabasePermissionManagement.java']