add note on calling methods more than once

README.md

@@ -222,6 +222,8 @@ The gem makes no assumption on a response's content type or what the migration
 will do. You could, for example, migrate the response body, or mutate the
 headers, or even change the response's status code.
 
+The `response` method can be used multiple times per-migration.
+
 ### Request migrations
 
 Request migrations define a change on a request. For example, modifying a request's
@@ -249,6 +251,8 @@ headers. It's up to you, all it does is provide the request.
 
 Request migrations should [avoid using the `migrate` method](#avoid-migrate-for-request-migrations).
 
+The `request` method can be used multiple times.
+
 ### Data migrations
 
 In our first scenario, where we combined our user's name attributes, we defined
@@ -322,6 +326,10 @@ be applied.
 
 In addition to data migrations, this allows for easier [testing](#testing).
 
+The `migrate` method can be used multiple times per-migration to e.g. 
+match and migrate on different shapes of data. For a JSON:API app,
+for example, you could migrate on `data: [*]` and `includes: [*]`.
+
 ### Routing constraints
 
 When you want to encourage API clients to upgrade, you can utilize a routing `version_constraint`