Add entry for golang (#40)

* Add entry for golang

* Update SUMMARY.md

* Update SUMMARY.md

Author: gadilashashank

book/SUMMARY.md

@@ -81,6 +81,20 @@
 
   * [Conclusion](languages/csharp/conclusion.md)
 
+* [Go](languages/golang/README.md)
+
+  * [Introduction](languages/golang/intro.md)
+
+  * [History](languages/golang/history.md)
+
+  * [Advantages](languages/golang/advantages.md)
+
+  * [Disadvantages](languages/golang/disadvantages.md)
+
+  * [Some interesting facts](languages/golang/misc.md)
+
+  * [Conclusion](languages/golang/conclusion.md)
+
 ## End
 
 * [Credits](credits.md)