Update app.py

app.py

@@ -3,7 +3,7 @@ import pandas as pd
 from sklearn.model_selection import train_test_split
 from sklearn.linear_model import LinearRegression
 from sklearn.tree import DecisionTreeRegressor
-from sklearn.ensemble import RandomForestRegressor
+from sklearn.ensemble import RandomForestRegressor, GradientBoostingRegressor
 from sklearn.model_selection import GridSearchCV
 
 # import joblib