adding clustering app description

apps/clustering.py

@@ -50,6 +50,13 @@ def to_excel(df: pd.DataFrame) -> bytes:
 
 st.title("Automatic Site Clustering App")
 
+# Add description
+st.write(
+    """This app allows you to cluster sites based on their latitude and longitude.
+    **Please choose a file containing the latitude and longitude region and site code columns.**
+                      """
+)
+
 uploaded_file = st.file_uploader("Upload your Excel file", type=["xlsx"])
 
 if uploaded_file: