SSO Login Demo

1. https://github.com/making/oauth2-sso-demo
2. https://github.com/making/demo-oauth2-login
3. https://github.com/oktadeveloper/okta-spring-boot-oauth-example
4. https://hellokoding.com/hello-single-sign-on-sso-with-json-web-token-jwt-spring-boot/
5. https://spring.io/guides/tutorials/spring-boot-oauth2/