Unfortunately, you need to have compensation in order to contribute to a Roth IRA.
Per the IRS, for an individual who is not self-employed, compensation means wages, tips, and other compensation from the employer subject to income tax withholding under section 3401(a). If you are self-employed, compensation is the net income (profits) earned by your business.
For more information on IRA contribution limits, please see https://www.irs.gov/retirement-plans/plan-participant-employee/retirement-topics-ira-contribution-li...