Use SQLite for session storage

Upgrade via to v0.2.5 and switch from in-memory sessions to SQLite-backed
sessions for persistence across server restarts.

main.go

@@ -25,11 +25,17 @@ func main() {
 	queries = gen.New(db.DB)
 	store.SetPersister(db.NewGamePersister(queries))
 
+	sessionManager, err := via.NewSQLiteSessionManager(db.DB)
+	if err != nil {
+		log.Fatal(err)
+	}
+
 	v := via.New()
 	v.Config(via.Options{
-		LogLvl:        via.LogLevelDebug,
-		DocumentTitle: "Connect 4",
-		ServerAddress: ":7331",
+		LogLvl:         via.LogLevelDebug,
+		DocumentTitle:  "Connect 4",
+		ServerAddress:  ":7331",
+		SessionManager: sessionManager,
 	})
 
 	v.AppendToHead(