SentimentAnalyzer on Amazon review dataset - Findings

This issue is a part of [Google Code-in 2019 task](https://codein.withgoogle.com/dashboard/task-instances/5933648059039744/). As a part of the task I'm reporting my findings on running the pre-trained SentimentAnalyzer with the [Amazon review dataset](https://www.kaggle.com/bittlingmayer/amazonreviews) as requested.

I found the accuracy of the model to be 51.71916007215394 percent.

Also, I found this issue https://github.com/JuliaText/TextAnalysis.jl/issues/160 and for that I simply ignored all such instances where the error was being reported. I found out the difference is very low and hence can be neglected.

I've also uploaded the notebook file to the GCI website.

cc @aviks @Ayushk4 @dhairyagandhi96