docs: go example

Author: AidasK

samples/Backend on Go.md

@@ -4,7 +4,7 @@
  * http://godoc.org/github.com/patdek/gongflow
  * https://github.com/stuartnelson3/golang-flowjs-upload
 
-## Exmaple 
+## Example 
 1. A `GET` request is sent to see if a chunk exists on disk. If it isn't found, the chunk is uploaded.
 2. Each `POST` request is parsed and then saved to disk.
 3. After the final chunk is uploaded, the chunks are stitched together in a separate go routine.