Merge #1350

1350: Update README.md to include Seesaw r=poteto a=kristenmthayer

Update README.md to include Seesaw; I think I did it right this time.

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## Add/Update/Remove <CompanyName>

- [x] I have read the [contributing guidelines](https://github.com/poteto/hiring-without-whiteboards/blob/master/CONTRIBUTING.md)
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Co-authored-by: Kristen Thayer <kristenmthayer@gmail.com>

README.md

@@ -758,6 +758,7 @@ Also check out [No Whiteboards](https://www.nowhiteboard.org) to search for jobs
 - [SC5 Online](https://sc5.io/careers) | Helsinki, Finland; Jyväskylä, Finland | Take-home assignment (intentionally short, takes at most an hour to complete), discussion and review assignments
 - [Scapic](https://scapic.com/careers/) | Bangalore, India | Short takehome project + phone interview
 - [Schibsted Tech Polska](https://www.schibsted.pl) | Gdańsk, Poland | Phone screen, take-home exercise, code review and technical discussion
+- [Seesaw](https://web.seesaw.me/about) | Remote | Technical challenges based on real world problems
 - [Segment](https://segment.com) | San Francisco, CA; Vancouver, Canada | Phone interview, take-home assignment (small fun project), onsite interview (technical + core/culture) -> intended to set you up for success
 - [SEITENBAU](https://www.seitenbau.com/karriere/aktuelle-jobangebote) | Konstanz, Germany | Peer recruiting; conversational interviews (video call or face-to-face) with other developers and HR focussing on motivation, attitude, skills; possibly 2nd face-to-face interview meeting with additional team members
 - [Sendyne](http://www.sendyne.com) | New York City, USA | Phone screen, on-site with team members. Review of past experiences + questions regardnig real problems.