add link to other solutions for the Angular/SpringBoot issue

pdb-ui/src/main/java/org/lucares/pdbui/WebConfiguration.java

@@ -40,6 +40,9 @@ public class WebConfiguration implements WebMvcConfigurer, HardcodedValues, Prop
      * This is one way to make Angular and SpringBoot play together. The other
      * described in {@link #addViewControllers(ViewControllerRegistry)}.
      * 
+     * Other solutions:
+     * https://stackoverflow.com/questions/38516667/springboot-angular2-how-to-handle-html5-urls/46854105#46854105
+     * 
      * @param registry
      */
     @SuppressWarnings("unused")
@@ -70,6 +73,9 @@ public class WebConfiguration implements WebMvcConfigurer, HardcodedValues, Prop
     /**
      * This is one way to make Angular and SpringBoot play together. The other
      * described in {@link #addResourceHandlerForAngular(ResourceHandlerRegistry)}
+     * 
+     * Other solutions:
+     * https://stackoverflow.com/questions/38516667/springboot-angular2-how-to-handle-html5-urls/46854105#46854105
      */
     @Override
     public void addViewControllers(final ViewControllerRegistry registry) {