Update app.py

app.py

@@ -138,6 +138,13 @@ intro_fields: List[Field] = [
     ]),
 ]
 
+end_fields: List[Field] = [
+    Field(type="container", title="**Thank you for taking part in this study!**", children=[
+        Field(name="email", type="textarea", title="Enter an email address where we can send you the voucher? *Without this, we cannot recompense you for your contribution to our research.*"),
+    ]),
+]
+
+
 fields: List[Field] = [
     Field(name="topic", type="input_col", title="**Topic:**"),
     Field(type="expander", title="**Preceeding Comment:** *(expand)*", children=[
@@ -454,8 +461,12 @@ elif st.session_state.current_index < len(st.session_state.data):
     with st.form("data_form"+str(st.session_state.current_index)):
         show_fields(fields)
 
+elif st.session_state.current_index == len(st.session_state.data):
+    with st.form("intro_form"):
+        show_fields(end_fields)
+    
 else:
-    st.write(f"Thank you for taking part in this study! [Click here]({https://app.prolific.com/submissions/complete?cc=CE552C7F}) to complete the study.")
+    st.write(f"Thank you, again! You are all done.")
 
 # Navigation buttons
 if st.session_state.current_index > 0: