Roth IRA and Employer-sponsored Roth contributions are not recorded anywhere on your tax return for a deduction. Enter your W-2 data only for an employer sponsored Roth.
If you qualify, you can enter your Roth Contributions in the Retirement Savings Contribution Credit section. This is a credit for certain middle-income taxpayers with other qualifying requirements. See link below for the requirements.
https://ttlc.intuit.com/questions/1900486-what-is-the-saver-s-credit
[4/18/17]
Roth contributions through an employer are either employee contributions to a Designated Roth Account in an employer plan, reported in box 12 of the employee's W-2, or they are Payroll Deduction Contributions to a Roth IRA which are regular Roth IRA contributions made to the individual's personal Roth IRA account, not an employer plan. In either case the amount *should* be entered into TurboTax because the contribution could qualify for a Retirement Savings Contributions Credit which *would* be recorded on the tax return.
I will edit to reflect the possibility of a saver's credit for lower income saver's but Roth IRA aren't required to be entered in the IRA section at all.
Enter amounts shown in box 12 of your W-2 only in box 12 of TurboTax's W-2 form.