Label the connection with the repo name (#698)

See elixir-ecto/db_connection#332

Author: nathanl

lib/ecto/adapters/sql.ex

@@ -895,7 +895,7 @@ defmodule Ecto.Adapters.SQL do
     {name, config} = Keyword.pop(config, :name, config[:repo])
     {pool_count, config} = Keyword.pop(config, :pool_count, 1)
     {pool, config} = pool_config(config)
-    child_spec = connection.child_spec(config)
+    child_spec = connection.child_spec([label: name] ++ config)
 
     meta = %{
       telemetry: telemetry,