Generate scripts to create DB Users and their membership from existing DB

-- Create script to create the DB Users
SELECT 'CREATE USER [' + name + '] for login [' + name + ']' + char(13) + 'GO'
 from sys.database_principals
 where Type = 'S' AND default_schema_name='dbo'

-- Create script to create the Users' membership
SELECT 'EXECUTE sp_AddRoleMember ''' + roles.name + ''', ''' + users.name + '''' + char(13) + 'GO'
 from sys.database_principals users
  inner join sys.database_role_members link
   on link.member_principal_id = users.principal_id
  inner join sys.database_principals roles
   on roles.principal_id = link.role_principal_id
 WHERE users.Type = 'S' AND users.default_schema_name='dbo'