Update CONTRIBUTING.md

Author: narendasan

CONTRIBUTING.md

@@ -42,7 +42,7 @@ You can quickly spell check with
 rake proof
 ```
 
-Depending on your platform, words will be flagged that are correctly spelled (our baseline will be dictionaries-common on Ubuntu 12.04). So if you are 100% sure a word is correctly spelled then add it in all caps to ```mdspell.config``` so it will not be flagged.
+Depending on your platform, words will be flagged that are correctly spelled (our baseline will be dictionaries-common on Ubuntu 12.04). So if you are 100% sure a word is correctly spelled then add it in all caps to ```dictionary.yml``` so it will not be flagged.
 
 To run the full test suite run