Fix command to train defect/enhancement/task model (#476)

* Fix command to train defect/enhancement/task model

Fixes #475

* Add more logging in the trainer script, and assert the model is generated

infra/dockerfile.train_defectenhancementtask

@@ -1,3 +1,3 @@
 FROM mozilla/bugbug-base:latest
 
-CMD bugbug-train defect
+CMD bugbug-train defectenhancementtask

scripts/trainer.py

@@ -43,9 +43,14 @@ class Trainer(object):
         model = model_class()
         model.train()
 
+        logger.info(f"Training done")
+
         model_file_name = f"{model_name}model"
+        assert os.path.exists(model_file_name)
         self.compress_file(model_file_name)
 
+        logger.info(f"Model compressed")
+
 
 def main():
     description = "Train the models"