add app.py (#3)

- add app.py (d92d857db0566a4b33e1eebef73b3933bbd595ca)


Co-authored-by: Chenzhao Wang <moiralala@users.noreply.huggingface.co>

app.py

@@ -0,0 +1,4 @@
+import streamlit as st
+
+x = st.slider('Select a value')
+st.write(x, 'squared is', x * x)