Update README.md

[sonyarianto]

Please note that for legal reasons we require you to sign the
Contributor Agreement
before we can accept your pull requests.

[jsteemann]

Hi @sonyarianto,

Many thanks for your PR!
We are using an Apache 2 contributor license agreement (CLA) for ArangoDB and its companion projects, which for legal reasons we require to get signed once by each contributor.
The CLA can be found here: https://www.arangodb.com/documents/cla.pdf
In order to accept your changes may you just fill in the form, sign and send a scanned copy over to cla[at]arangodb[.]com or via fax to +49-221-2722999-88
Thanks very much!

[sonyarianto]

@jsteemann Hi, I already send the CLA to e-mail, thanks.

[jsteemann]

Thanks!