Add ability to get key from rest server

[AlexeyZatsepin]

#include <boost/asio.hpp>

int main() {
boost::system::error_code ec;
using namespace boost::asio;

// what we need
io_service svc;
ip::tcp::socket sock(svc);
sock.connect({ {}, 8087 }); // http://localhost:8087 for testing

// send request
std::string request("GET /newGame?name=david HTTP/1.1\r\n\r\n");
sock.send(buffer(request));

// read response
std::string response;

do {
    char buf[1024];
    size_t bytes_transferred = sock.receive(buffer(buf), {}, ec);
    if (!ec) response.append(buf, buf + bytes_transferred);
} while (!ec);

// print and exit
std::cout << "Response received: '" << response << "'\n";

}