impl config State and config Interval

config/config.go

@@ -1,7 +1,35 @@
 package config
 
-import "errors"
+import (
+	"encoding/json"
+	"io/ioutil"
+	"os"
+)
+
+type Config struct {
+	Interval Duration
+	States   []State
+}
+
+var live Config
 
 func Refresh() error {
-	return errors.New("not impl")
+	configPath, ok := os.LookupEnv("CONFIG")
+	if !ok {
+		configPath = "./config.json"
+	}
+	b, err := ioutil.ReadFile(configPath)
+	if err != nil {
+		return err
+	}
+	var c Config
+	if err := json.Unmarshal(b, &c); err != nil {
+		return err
+	}
+	live = c
+	return nil
+}
+
+func Get() Config {
+	return live
 }