Add kill command.

README.md

@@ -321,7 +321,7 @@ The feature page grabs its content automatically from the file
 ### Create or update the comparison pages (under `/comparison`)
-The [comparison page][comp] grabs its content automatically from 
+The [comparison page][comp] grabs its content automatically from
 `data/comparisons.yml`.
 There are 3 files in total which you need to create or edit:
@@ -689,6 +689,7 @@ Beware that:
 In case someone forgot the most important commands and is catting this file from the command line we end by listing them:
 ```
+kill -kill `lsof -t -i tcp:4567`
 bundle exec rake new_post
 bundle exec middleman
 ```