Add your name to the list of the ops in this file: /path_to_server_folder/config/de.yottaflops.permanentnightvision.conf
Start the server again
When you finished this, you don’t have to restart the server over and over again to add new ops. To do that you can just edit the config file and then do /light reload in Minecraft.
So I decided to take my project into a slightly different direction. The latest release contains a variety of potion effects now, All with configurable messages, and you can now apply effects to other players, if you have permission. They are all modular therefore any potion effects you don’t want to use can be disabled in the config. To align with the new direction, the project has been renamed, and commands have slightly changed as well as permission nodes. More details here if you are interested.