I have database project (.sqlproj) in Visual Studio where I create user like this:
CREATE USER [MyUser] WITHOUT LOGIN; --I dont want to store password in source control
GO
ALTER ROLE [db_datareader] ADD MEMBER [MyUser]
GO
ALTER ROLE [db_datawriter] ADD MEMBER [MyUser]
GO
ALTER ROLE [db_executor] ADD MEMBER [MyUser]
I build dacpack in VSTS Build and deploy it to Azure in VSTS Release:
How do I setup the continuous deployment so that it will create user with password?
This plug-in in Azure Marketplace maybe useful.
You can also create logins using PowerShell and include conditional execution.
More alternatives explained here.
Hope this helps.