Add flashcard count to /statistics

src/main/java/de/thm/arsnova/dao/CouchDBDao.java

@@ -1282,6 +1282,9 @@ public class CouchDBDao implements IDatabaseDao, ApplicationEventPublisherAware
 					case "conceptQuestions":
 						stats.setConceptQuestions(stats.getConceptQuestions() + value);
 						break;
+					case "flashcards":
+						stats.setFlashcards(stats.getFlashcards() + value);
+						break;
 					}
 				}
 			}

src/main/java/de/thm/arsnova/entities/Statistics.java

@@ -37,6 +37,7 @@ public class Statistics {
 	private int loggedinUsers;
 	private int interposedQuestions;
 	private int conceptQuestions;
+	private int flashcards;
 
 	@ApiModelProperty(required = true, value = "the number of answers")
 	public int getAnswers() {
@@ -120,6 +121,15 @@ public class Statistics {
 		this.interposedQuestions = interposedQuestions;
 	}
 
+	@ApiModelProperty(required = true, value = "the number of flashcards")
+	public int getFlashcards() {
+		return flashcards;
+	}
+
+	public void setFlashcards(int flashcards) {
+		this.flashcards = flashcards;
+	}
+
 	@ApiModelProperty(required = true, value = "the number of creators")
 	public int getCreators() {
 		return creators;