fix start, edit readme

spring-5-security-oauth/README.md

@@ -1,3 +1,4 @@
 ## Relevant articles:
 
-- [Spring Security 5 -OAuth2 Login](http://www.baeldung.com/spring-security-5-oauth2-login)
+- [Spring Security 5 -OAuth2 Login](http://www.baeldung.com/spring-security-5-oauth2-login)
+- [Extracting Principal and Authorities using Spring Security OAuth](https://www.baeldung.com/spring-security-oauth-principal-authorities-extractor)

spring-5-security-oauth/pom.xml

@@ -67,6 +67,7 @@
 	
     <properties>
         <oauth-auto.version>2.0.1.RELEASE</oauth-auto.version>
+        <start-class>com.baeldung.oauth2.SpringOAuthApplication</start-class>
     </properties>
 
 </project>