func NewBroker(c *Config) *Broker {
	baseURL, _ := url.Parse(defaultBaseURL)
	return &Broker{
		Config:  c,
		BaseURL: baseURL,
	}
}
NewBroker create a Broker.
package qiisync
import (
	"bytes"
	"encoding/json"
	"errors"
	"fmt"
	"io"
	"io/ioutil"
	"net/http"
	"net/url"
	"os"
	"path/filepath"
	"regexp"
	"strconv"
	"strings"
	"time"
)
var (
	defaultBaseURL      = "https://qiita.com/"
	defaultItemsPerPage = 20
	defaultExtension    = ".md"
	invalidCharacterReg = regexp.MustCompile(`[\\\/?:*"<>|]`)
)
type Broker struct {
	*Config
	BaseURL *url.URL
}