Add description to card metadata

ROUGE, or Recall-Oriented Understudy for Gisting Evaluation, is a set of metrics and a software package used for
evaluating automatic summarization and machine translation software in natural language processing.
The metrics compare an automatically produced summary or translation against a reference or a set of references (human-produced) summary or translation.

Note that ROUGE is case insensitive, meaning that upper case letters are treated the same way as lower case letters.

This metrics is a wrapper around Google Research reimplementation of ROUGE:
https://github.com/google-research/google-research/tree/master/rouge

README.md

@@ -1,6 +1,6 @@
 ---
 title: ROUGE
-emoji: 🤗 
+emoji: 🤗
 colorFrom: blue
 colorTo: red
 sdk: gradio
@@ -8,10 +8,27 @@ sdk_version: 3.0.2
 app_file: app.py
 pinned: false
 tags:
-- evaluate
-- metric
----
+  - evaluate
+  - metric
+description: >-
+  ROUGE, or Recall-Oriented Understudy for Gisting Evaluation, is a set of
+  metrics and a software package used for
+
+  evaluating automatic summarization and machine translation software in natural
+  language processing.
+
+  The metrics compare an automatically produced summary or translation against a
+  reference or a set of references (human-produced) summary or translation.
+
 
+  Note that ROUGE is case insensitive, meaning that upper case letters are
+  treated the same way as lower case letters.
+
+
+  This metrics is a wrapper around Google Research reimplementation of ROUGE:
+
+  https://github.com/google-research/google-research/tree/master/rouge
+---
 # Metric Card for ROUGE
 
 ## Metric Description