Fix rm_user task.

lib/mix/tasks/rm_user.ex

@@ -1,14 +1,14 @@
 defmodule Mix.Tasks.RmUser do
   use Mix.Task
   import Mix.Ecto
-  alias Pleroma.User
+  alias Pleroma.{User, Repo}
 
   @shortdoc "Permanently delete a user"
   def run([nickname]) do
     ensure_started(Repo, [])
 
     with %User{local: true} = user <- User.get_by_nickname(nickname) do
-      user.delete()
+      User.delete(user)
     end
   end
 end