After "mix phx.gen.auth Admins Admin admins" with added working register and login path.

lib/beet_round_server_web/controllers/admin_registration_controller.ex

@@ -0,0 +1,32 @@
+defmodule BeetRoundServerWeb.AdminRegistrationController do
+  use BeetRoundServerWeb, :controller
+
+  alias BeetRoundServer.Admins
+  alias BeetRoundServer.Admins.Admin
+
+  def new(conn, _params) do
+    changeset = Admins.change_admin_email(%Admin{})
+    render(conn, :new, changeset: changeset)
+  end
+
+  def create(conn, %{"admin" => admin_params}) do
+    case Admins.register_admin(admin_params) do
+      {:ok, admin} ->
+        {:ok, _} =
+          Admins.deliver_login_instructions(
+            admin,
+            &url(~p"/admins/log-in/#{&1}")
+          )
+
+        conn
+        |> put_flash(
+          :info,
+          "An email was sent to #{admin.email}, please access it to confirm your account."
+        )
+        |> redirect(to: ~p"/admins/log-in")
+
+      {:error, %Ecto.Changeset{} = changeset} ->
+        render(conn, :new, changeset: changeset)
+    end
+  end
+end