Update app.py

app.py

@@ -14,6 +14,9 @@ import vega_datasets
 
 #load data 
 df2=pd.read_csv("https://raw.githubusercontent.com/dallascard/SI649_public/main/altair_hw3/approval_topline.csv")
+df2['timestamp']=pd.to_datetime(df2['timestamp'])
+df2=pd.melt(df2, id_vars=['president', 'subgroup', 'timestamp'], value_vars=['approve','disapprove']).rename(columns={'variable':'choice', 'value':'rate'})
+
 # Import panel and vega datasets
 
 import panel as pn