rm_user: also ensure that cache is running.

lib/mix/tasks/rm_user.ex

@@ -5,7 +5,7 @@ defmodule Mix.Tasks.RmUser do
 
   @shortdoc "Permanently delete a user"
   def run([nickname]) do
-    ensure_started(Repo, [])
+    Mix.Task.run("app.start")
 
     with %User{local: true} = user <- User.get_by_nickname(nickname) do
       User.delete(user)