Update README.md

Asubset of amazon review data by He, R.; and McAuley, J. J. 2016. Ups and Downs: Modeling the Visual Evolution of Fashion Trends with One-Class Collaborative Filtering. In WWW, 507–517. ACM
Since it is not possible to use all the dataset because of it's big size. I created thus subset where each category is represented by 1200 lines.
Hope this help

README.md

@@ -1,3 +1,11 @@
 ---
 license: mit
----
+language:
+- en
+tags:
+- review,
+- training,
+- amazon
+- subset
+pretty_name: amazon-review-subset
+---