use credo style

lib/memex/repo/migrator.ex

@@ -6,11 +6,11 @@ defmodule Memex.Repo.Migrator do
   use GenServer
   require Logger
 
-  def start_link(_) do
+  def start_link(_opts) do
     GenServer.start_link(__MODULE__, [], [])
   end
 
-  def init(_) do
+  def init(_opts) do
     migrate!()
     {:ok, nil}
   end