Add JDBC user details to web-secure sample

See gh-1115

spring-boot-samples/spring-boot-sample-web-secure/src/main/resources/schema.sql

@@ -0,0 +1,10 @@
+create table users (
+  username varchar(256),
+  password varchar(256),
+  enabled boolean
+);
+
+create table authorities (
+  username varchar(256),
+  authority varchar(256)
+);