http://docs.spring.io/spring-boot/docs/1.2.3.RELEASE/reference/html/boot-features-external-config.html#boot-features-external-config-loading-yaml

http://docs.spring.io/spring-boot/docs/1.2.3.RELEASE/reference/html/boot-features-external-config.html#boot-features-external-config-placeholders-in-properties

http://docs.spring.io/spring-boot/docs/1.2.3.RELEASE/reference/html/boot-features-profiles.html#boot-features-profile-specific-configuration

https://docs.spring.io/spring-boot/docs/current/reference/html/boot-features-external-config.html#boot-features-external-config-application-property-files

http://docs.spring.io/spring-boot/docs/current/reference/html/howto-properties-and-configuration.html