RNN Personalized for every user

Question

I want to build an RNN sequence prediction that is personalized for every user according to userID. The RNN behaviour is something like this

user ID -> [var1, var2, var3, var4, var5]

The RNN should predict var5. Should I include user ID as the first item in the sequence so it would look like this

[userid, var1, var2, var3, var4, var5]

or I should build an RNN for every user or there is a way of implementing that ?