Add description to card metadata

This metric wrap the official scoring script for version 1 of the Stanford Question Answering Dataset (SQuAD).

Stanford Question Answering Dataset (SQuAD) is a reading comprehension dataset, consisting of questions posed by
crowdworkers on a set of Wikipedia articles, where the answer to every question is a segment of text, or span,
from the corresponding reading passage, or the question might be unanswerable.

README.md

@@ -1,6 +1,6 @@
 ---
 title: SQuAD
-emoji: 🤗 
+emoji: 🤗
 colorFrom: blue
 colorTo: red
 sdk: gradio
@@ -8,10 +8,21 @@ sdk_version: 3.0.2
 app_file: app.py
 pinned: false
 tags:
-- evaluate
-- metric
----
+  - evaluate
+  - metric
+description: >-
+  This metric wrap the official scoring script for version 1 of the Stanford
+  Question Answering Dataset (SQuAD).
+
+
+  Stanford Question Answering Dataset (SQuAD) is a reading comprehension
+  dataset, consisting of questions posed by
 
+  crowdworkers on a set of Wikipedia articles, where the answer to every
+  question is a segment of text, or span,
+
+  from the corresponding reading passage, or the question might be unanswerable.
+---
 # Metric Card for SQuAD
 
 ## Metric description