Add citation information to dataset card (#3)

- Add citation information to dataset card (756dc2f1700784852a0ba8640c0c5b9bd4fc899c)

README.md

@@ -165,7 +165,28 @@ Portuguese dataset for hate speech detection composed of 5,668 tweets with binar
 
 ### Citation Information
 
-[More Information Needed]
+```
+@inproceedings{fortuna-etal-2019-hierarchically,
+    title = "A Hierarchically-Labeled {P}ortuguese Hate Speech Dataset",
+    author = "Fortuna, Paula  and
+      Rocha da Silva, Jo{\~a}o  and
+      Soler-Company, Juan  and
+      Wanner, Leo  and
+      Nunes, S{\'e}rgio",
+    editor = "Roberts, Sarah T.  and
+      Tetreault, Joel  and
+      Prabhakaran, Vinodkumar  and
+      Waseem, Zeerak",
+    booktitle = "Proceedings of the Third Workshop on Abusive Language Online",
+    month = aug,
+    year = "2019",
+    address = "Florence, Italy",
+    publisher = "Association for Computational Linguistics",
+    url = "https://aclanthology.org/W19-3510",
+    doi = "10.18653/v1/W19-3510",
+    pages = "94--104",
+}
+```
 
 ### Contributions