When you're setting up your database to conform to the Poll struct, you need to add these lines to your configure.swift file, within configure() throws { //here }:

var migrationConfig = MigrationConfig() migrationConfig.add(model: Poll.self, database: .sqlite) services.register(migrationConfig)

When you do, you get the error: "Reference to member 'sqlite' cannot be resolved without a contextual type"

To resolve this, replace .sqlite with DatabaseIdentifier<Poll.Database>.sqlite.