update d3 on zeppelin example with external json

[stillalex]

First off, thanks for the examples! for me it was a perfect way of building a small POC.

It would be nice if you could update the d3 zeppelin example to show how to use an external json, I found that to be a bit tricky to get right (even though it's a 2 liner):

val dataS3 = spark.read.json("s3://bucket/file.json")
val data = dataS3.toJSON.head

I could also go for a pull request if you want.

thanks again,
alex

[nelsonjiao]

I am running trouble with d3 zappelin example too. (error of non recognized json) And I am not sure how to use the two lines. Can you please give more detail steps?

Thanks

Nelson