Got usernames working, for now, I think.

apps/bwc/lib/bwc.ex

@@ -11,12 +11,23 @@ defmodule Bwc do
 
   def create_player(attrs), do: Player.changeset(%Player{}, attrs) |> @repo.insert()
 
-  def delete_player(id), do: get_player(id) |> @repo.delete
+  def delete_player(nil), do: {:error, "Player does not exist"}
+  def delete_player(%Player{} = player), do: player |> @repo.delete
 
-  def list_players, do: @repo.all(Player)
+
+  def reset, do: Bwc.list_players |> Enum.each(fn(p) -> Bwc.delete_player(p) end)
+
+  def change_name({old_username, new_username}) do
+    {:ok, old_player} = old_username |> Bwc.get_or_create_player
+    old_player |> Player.changeset(%{username: new_username}) |> @repo.update()
+  end
+
+  def list_players, do: @repo.all(Player) |> Enum.filter(fn(p) -> p.username != "Nobody" end)
 
   def get_player(id), do: @repo.get!(Player, id)
 
+  def get_player_by_username(username), do: get_player_by(%{username: username})
+
   def get_player_by(params), do: @repo.get_by(Player, params)
 
   def get_or_create_player(username) do