Update datasets.md

Added labelled data for Sentiment Analysis.

Author: acquayefrank

datasets.md

@@ -33,3 +33,8 @@
 ### Curated Lists of Datasets
 
 * [@hmason's](https://twitter.com/hmason) curated dataset list [bit.ly](https://bitly.com/bundles/hmason/1)
+
+### Sentiment Analysis
+* https://github.com/acquayefrank/sanders-twitter
+* https://www.kaggle.com/c/sentiment-analysis-on-movie-reviews/data
+* http://ai.stanford.edu/~amaas/data/sentiment/