Update README

README.md

@@ -1,13 +1,22 @@
 # go-timezone
 
-Timezone utility for Go
-
-[![GoDocWidget]][GoDocReference]
+[![GoDocWidget]][GoDocReference] ![Test](https://github.com/tkuchiki/go-timezone/workflows/Test/badge.svg)
 
 [GoDocWidget]:https://godoc.org/github.com/tkuchiki/go-timezone?status.svg
 [GoDocReference]:https://godoc.org/github.com/tkuchiki/go-timezone
 
-![Test](https://github.com/tkuchiki/go-timezone/workflows/Test/badge.svg)
+----
+
+go-timezone is timezone utility for Go.  
+
+It has the following features:
+
+- This library uses only the standard package
+- Supports getting offset from timezone abbreviation, which is not supported by the time package
+- Determine whether the specified time.Time is daylight saving time
+- Change the location of time.Time by specifying the timezone
+
+See [godoc][GoDocReference] for usage.
 
 ## Data source