Revised the gestures of the server adapter

app/src/main/java/com/cappielloantonio/play/database/dao/ServerDao.java

@@ -20,6 +20,12 @@ public interface ServerDao {
     @Insert(onConflict = OnConflictStrategy.REPLACE)
     void insert(Server server);
 
+    @Insert(onConflict = OnConflictStrategy.REPLACE)
+    void insertAll(List<Server> servers);
+
     @Delete
     void delete(Server server);
+
+    @Query("DELETE FROM server")
+    void deleteAll();
 }