Switch to side-by-side view

--- a
+++ b/recommendation-engine/src/main/java/eu/alfred/personalization_manager/model/HistoricalEntryCategories.java
@@ -0,0 +1,15 @@
+package eu.alfred.personalization_manager.model;
+
+public enum HistoricalEntryCategories {
+
+	EVENTS_PARTICIPATED,
+	EVENTS_DENIED,
+	EVENTS_SEARCHED,
+	GAMES_PLAYED,
+	GAMES_DENIED,
+	GAMES_SEARCHED,
+	APPS_INSTALLED,
+	APPS_UNINSTALLED,
+	CONTACTS_SOCIALIZED_WITH,
+	
+}