Ensembling in titanic dataset

Hey guyz, i wanted to know about ensembling, and are we allowed to that on this training set, because the title mentions only random forest as a predictive algorithm. And if we are allowed then i would like to get some help with ensembling because while ensembling i get following error “Something is wrong all the accuracy measures are missing”. As the Survived feature in test doesn’t include any values, i added 0 for all the the ID’s and made it a factor with two variables after i joined it with train variable, now when i try to predict with y = Survived. It gives me the above error.

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