How to auto merge pr

[utkarshsethi]

Description

Just added documentation on how to auto merge pr if someone so desired.

Fixes #213

Checklist

• [x] I have squashed my commits into a single one with a message that aligns with the contributing guidelines
• [x] My code follows the style guidelines of this project
• [x] I have performed a self-review of my own code
• [x] I have commented my code, particularly in hard-to-understand areas
• [x] I have made corresponding changes to the documentation
• [x] I have added tests that prove my fix is effective or that my feature works

[FantasticFiasco]

Thanks for the PR! I'll review it in the upcoming days.

[coveralls]

Coverage remained the same at 90.816% when pulling dea04574dc689f0d5c11512913d317b5e386b25e on utkarshsethi:auto-merge-pr into a23f32b17e2fcc9986a99fc2a84eafce7b97e5e2 on FantasticFiasco:master.