Add bob's feature

dengue_prediction/features/contrib/user_bob.py

@@ -0,0 +1,12 @@
+from fhub_transformers.missing import LagImputer
+from fhub_transformers.ts import SingleLagger
+from sklearn.preprocessing import Imputer
+
+groupby_kwargs = {'level': ['city', 'weekofyear']}
+
+input = 'reanalysis_max_air_temp_k'
+transformer = [
+    LagImputer(groupby_kwargs=groupby_kwargs),
+    SingleLagger(2, groupby_kwargs=groupby_kwargs),
+    Imputer(),
+]