Update README

Author: MadhavBahl

README.md

@@ -23,6 +23,7 @@ Read [CONTRIBUTING.md](./CONTRIBUTING.md) for contribution guidelines.
 4. [Day 4 -- Num Vowels + Max Chars](./day4/) -- [http://codetoexpress.tech/dc/day4/](http://codetoexpress.tech/dc/day4/)
 5. [Day 5 -- Pattern Printing Problems](./day5/) -- [http://codetoexpress.tech/dc/day5/](http://codetoexpress.tech/dc/day5/)
 6. [Day 6 -- Sentence Cap + Word Reversal + Anagram](./day6/) -- [http://codetoexpress.tech/dc/day6/](http://codetoexpress.tech/dc/day6/)
+7. [Day 7 -- One Edit Away](./day7/) -- [http://codetoexpress.tech/dc/day7/](http://codetoexpress.tech/dc/day7/)
 
 ## Timeline