Update changelog upgrade instructions

Author: danschultzer

CHANGELOG.md

@@ -8,9 +8,24 @@ This is a full rewrite of the library, and are several breaking changes. You're
 
 Read the [ExOauth2Provider](https://github.com/danschultzer/ex_oauth2_provider) CHANGELOG.md for upgrade instructions.
 
-### 2. Routes
+### 2. Configuration
 
-Routes are now separated into api and non api routes. Update your routes like so:
+Configuration has been split up so now it should look like this (`:module` and `:current_resource_owner` should be moved to the separate configuration for PhoenixOauth2Provider):
+
+```elixir
+config :my_app, ExOauth2Provider,
+  repo: MyApp.Repo,
+  resource_owner: MyApp.Users.User,
+  # ...
+
+config :my_app, PhoenixOauth2Provider,
+  current_resource_owner: :current_user,
+  web_module: MyAppWeb
+```
+
+### 3. Routes
+
+Routes are now separated into api and non api routes. Remove the old `oauth_routes/1` routes, and update your `router.ex` to look like this instead:
 
 ```elixir
 defmodule MyAppWeb.Router do
@@ -39,6 +54,12 @@ defmodule MyAppWeb.Router do
 end
 ```
 
-### 3. Templates and views
+Remember to remove the `:oauth_public` pipeline. The default `:api` pipeline will be used instead.
+
+### 4. Templates and views
+
+Remove the old `module: MyApp` setting in your PhoenixOauth2Provider configuration, and instead set `web_module: MyAppWeb`.
+
+However, templates and views are no longer required to be generated so you can remove them and the `:web_module` configuration setting entirely if the default ones work for you.
 
-Update `:module` to `:web_module` in your configuration. Templates and views are no longer required to be generated so you can remove them entirely if the default ones work for you.
+The easiest migration of templates and views are to just delete the folders (`lib/my_app_web/templates/{application, authorization, authorized_application}` and `lib/my_app_web/views/phoenix_oauth2_provider`), and then run `mix phoenix_oauth2_provider.gen.templates` to regenerate them. Then you can go into the templates and update them to use your old markup.