feat #4: add storage config in config file

polyculeconnect/config/config.go

@@ -55,6 +55,7 @@ type OpenConnectConfig struct {
 }
 
 type StorageConfigConfig struct {
+	File     string `json:"file"`
 	Host     string `json:"host"`
 	Port     int    `json:"port"`
 	Database string `json:"database"`