Merge pull request #316 from BencicAndrej/readme-example-fix

Updated README in-memory example.

Author: mcuadros

README.md

@@ -77,7 +77,7 @@ ref, err := r.Head()
 CheckIfError(err)
 
 // ... retrieves the commit object
-commit, err := r.Commit(ref.Hash())
+commit, err := r.CommitObject(ref.Hash())
 CheckIfError(err)
 
 // ... retrieves the commit history