func fetchLessons(groupName: String, in container: Container) throws -> Future<KPIResponseContainer<[KPILesson]>> {

    let logger = try container.make(Logger.self)
    let client = HTTPClient.connect(scheme: .https, hostname: hostname, on: container)

    return client.flatMap(to: HTTPResponse.self) { client in
        guard
            let encodedGroupName = groupName.addingPercentEncoding(withAllowedCharacters: .urlQueryAllowed),
            let url = URLComponents(string: "/v2/groups/\(encodedGroupName)/lessons")?.url
        else {
            throw Abort(.badRequest, reason: "Invalid group name")
        }

        logger.debug("Sending request to http://\(self.hostname)\(url.path)")

        let request = HTTPRequest(method: .GET, url: url)
        return client.send(request)

    }.flatMap(to: KPIResponseContainer<[KPILesson]>.self) { httpResponse in

        let response = Response(http: httpResponse, using: container)
        return try response.content.decode(KPIResponseContainer<[KPILesson]>.self)
    }
}