How to set a specific Number as Next ID and Its Continuation to use as Primary Key on Creation of Next Record On wards in PL-SQL in my Rails-4 App?

If my Question title is not clear, Let me details it more: In my rails application, in local(development) I am using PL-SQL as my databse, and there is a Customer table where the Primary ID starts from 1,2,3.......so on. Till I start using the same database in Local(development) & Production there was no problem in creating customers, so after I started running Local(development) & Production in parallel with same DB many of the time customer creations fails as ID's trying to create as Duplicate. So how can I set in my Local/Production to change the next Index to start with for the ID into another number to avoid this conflict. ?

Eg: I want to continue using(1,2.....etc) the ID in Local & in production I want to set the next Id from 50000 on wards and continuation.