Switch to Config module

config/config.exs

@@ -3,7 +3,7 @@
 #
 # This configuration file is loaded before any dependency and
 # is restricted to this project.
-use Mix.Config
+import Config
 
 config :phoenix, :json_library, Jason
 
@@ -52,4 +52,4 @@ config :dart_sass,
 
 # Import environment specific config. This must remain at the bottom
 # of this file so it overrides the configuration defined above.
-import_config "#{Mix.env()}.exs"
+import_config "#{config_env()}.exs"

config/dev.exs

@@ -1,4 +1,4 @@
-use Mix.Config
+import Config
 
 # For development, we disable any cache and enable
 # debugging and code reloading.

config/prod.exs

@@ -1,4 +1,4 @@
-use Mix.Config
+import Config
 
 config :chess, ChessWeb.Endpoint,
   cache_static_manifest: "priv/static/cache_manifest.json",

config/test.exs

@@ -1,4 +1,4 @@
-use Mix.Config
+import Config
 
 # We don't run a server during test. If one is required,
 # you can enable the server option below.