fix: run migrator on startup

lib/localiser/migrator.ex

@@ -0,0 +1,13 @@
+defmodule Localiser.Migrator do
+  use GenServer
+
+  def start_link(args) do
+    GenServer.start_link(__MODULE__, args, name: __MODULE__)
+  end
+
+  def init(_args) do
+    path = Application.app_dir(:localiserd, "priv/repo/migrations")
+    Ecto.Migrator.run(Localiser.Repo, path, :up, all: true)
+    {:ok, %{}}
+  end
+end