Add an example on pool usage in the documentation

[ledsusop]

initial pull request and doc change

[landscape-bot]

Code quality remained the same when pulling 3107b39 on ledsusop:master into 7e50742 on airbnb:master.

[bolkedebruin]

Hi lusop. Thanks for the contribution! Please follow these http://chris.beams.io/posts/git-commit/ guidelines for your commit message. It helps creating changelogs and release notes in the future. Thanks!

[ledsusop]

alright @bolkedebruin , do you need me to reissue a pull request?

[bolkedebruin]

Just update your commit message. Git commit --amend , git push --force

[coveralls]

Coverage decreased (-0.1%) to 66.27% when pulling 3107b3967c8f5678dda61a6ec689caa04549b462 on ledsusop:master into 7e50742 on airbnb:master.

[ledsusop]

done

[landscape-bot]

Repository health increased by 0.02% when pulling 2f48a53 on ledsusop:master into 7a632e2 on airbnb:master.

• No new problems were introduced.
• 8 problems were fixed (including 0 errors and 0 code smells).

[coveralls]

Coverage remained the same at 66.377% when pulling 2f48a53 on ledsusop:master into 7a632e2 on airbnb:master.