examples: show how to use a before_request method for the multi-route examples, be more informative about DB creation problems (#16279)

examples/vweb/vweb_example.v

@@ -18,6 +18,10 @@ mut:
 	cnt int
 }
 
+pub fn (app App) before_request() {
+	println('[Vweb] $app.Context.req.method $app.Context.req.url')
+}
+
 fn main() {
 	println('vweb example')
 	vweb.run(&App{}, port)

examples/vweb_orm_jwt/src/main.v

@@ -11,12 +11,16 @@ struct App {
 	vweb.Context
 }
 
+pub fn (app App) before_request() {
+	println('[Vweb] $app.Context.req.method $app.Context.req.url')
+}
+
 fn main() {
 	mut db := databases.create_db_connection() or { panic(err) }
 
 	sql db {
 		create table User
-	}
+	} or { panic('error on create table: $err') }
 
 	db.close() or { panic(err) }