fix: remove memory leak

CHANGELOG.md

@@ -7,6 +7,10 @@ Which is based on [Keep A Changelog](http://keepachangelog.com/)
 
 ## Unreleased
 
+### Fixed
+
+- remove memory leak
+
 ## v1.0.1 - 2019-08-22
 
 ### Added

weather.go

@@ -62,6 +62,7 @@ type WeatherData struct {
 
 // FetchData from OpenWeatherMap API
 func (w *Weather) FetchData() {
+	w.WeatherDatas = []WeatherData{}
 	for _, city := range w.Config.Cities {
 		resp, err := http.Get(
 			fmt.Sprintf(