Update app.py

app.py

@@ -222,6 +222,8 @@ with gr.Blocks(css=css) as demo:
     with gr.Tab("Open letter: why are we doing this?"):
         gr.Markdown('''# ┌∩┐(◣_◢)┌∩┐ DEAR CORPORATE AI OVERLORDS ┌∩┐(◣_◢)┌∩┐
 
+        If this letter resonates with you add your signature [here](https://openletter.earth/dear-corporate-ai-overlords-90668a95).
+
 We received access to Sora with the promise to be early testers, red teamers and creative partners. However, we believe instead we are being lured into "art washing" to tell the world that Sora is a useful tool for artists. 
 
 <code style="font-family: monospace;font-size: 16px;font-weight:bold">ARTISTS ARE NOT YOUR UNPAID R&D <br />