java doc and readme update

src/main/java/ch/zhaw/gartenverwaltung/plantList/PlantListModel.java

@@ -99,7 +99,14 @@ public class PlantListModel {
         return plantList;
     }
 
-
+    /**
+     *
+     * @param zone selected hardiness zone
+     * @param searchString the string to search plant List, set '#' as first char the search by id.
+     * @return List of plants found in Plant List which contain the search String in the name or description
+     * @throws HardinessZoneNotSetException If no {@link HardinessZone} was specified
+     * @throws IOException If the database cannot be accessed
+     */
     public List<Plant> getFilteredPlantListByString(HardinessZone zone, String searchString) throws HardinessZoneNotSetException, IOException {
         if(searchString.charAt(0) == '#') {
             try {
@@ -111,6 +118,4 @@ public class PlantListModel {
             return getFilteredPlantList(zone, plant -> plant.name().contains(searchString) || plant.description().contains(searchString));
         }
     }
-
-
 }