fix(database): fix type of segment id that has no right to be a TEXT

I could not think of a reason why this table's id should be a text,
so I'm fairly sure it was a mistake. Back to INTEGER

lib/transport_helper.dart

@@ -101,7 +101,7 @@ class Route {
     Database database = DbHelper.db;
     String segment = Segment.tableName;
     database.execute("""CREATE TABLE IF NOT EXISTS routesegments(
-    id            TEXT PRIMARY KEY AUTOINCREMENT,
+    id            INTEGER PRIMARY KEY AUTOINCREMENT,
     route         INTEGER,
     segment       INTEGER,
     segmentorder  INTEGER, -- TODO: implement sorting