Gifted shirt coupons

[fridaland]

Add ability to gift shirts to incompleted users

In #437 we added the ability to gift sticker_coupons. This pull request will allow users to receive "gifted" t-shirt coupons as well.

Test process

Currently, we only allow completed users to receive shirt coupons.

Changes necessary:

• Update this rake task to reflect giving users any remaining available shirt coupons when that is implemented in CouponService
• Update CouponService to allow incompleted users to receive shirt coupons.
• Ensure pending coupon_service_specs are no longer pending
• Add a context in user_spec for there are shirt coupons available

Requirements to merge

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code in hard-to-understand areas
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes

[fridaland]

This will need to be rebased against master once #437 is merged.

[fridaland]