Added LendUp

[teddywilson]

We're super excited to be using GraphQL here at LendUp and had a blast at the summit a few weeks ago!

[facebook-github-bot]

Thank you for your pull request and welcome to our community. We require contributors to sign our Contributor License Agreement, and we don't seem to have you on file. In order for us to review and merge your code, please sign up at https://code.facebook.com/cla. If you are contributing on behalf of someone else (eg your employer), the individual CLA may not be sufficient and your employer may need the corporate CLA signed.

If you have received this in error or have any questions, please contact us at cla@fb.com. Thanks!

[caniszczyk]

We will be moving to a new landscape+page to track GraphQL users:
https://landscape.graphql.org/category=graph-ql-adopter&format=card-mode&grouping=category

Can you please add your entry here via pull request:
https://github.com/graphql/graphql-landscape#new-entries

You can see this example with Stackshare as an example:
graphql/graphql-landscape#48