Added migration chapter to documentation configuration

Author: weierophinney

mkdocs.yml

@@ -54,6 +54,7 @@ pages:
         - 'Expressive Projects': reference/expressive-projects.md
         - Migration:
             - 'From RC5 and Earlier': reference/migration/rc-to-v1.md
+            - 'To Expressive 1.1': reference/migration/to-v1-1.md
 site_name: Expressive
 site_description: 'zend-expressive: PSR-7 Middleware Microframework'
 repo_url: 'https://github.com/zendframework/zend-expressive'