test: implement dockertest for repositories

[rahmatrhd]

closes #242

[coveralls]

Pull Request Test Coverage Report for Build 3179747081

• 14 of 21 (66.67%) changed or added relevant lines in 1 file are covered.
• 34 unchanged lines in 6 files lost coverage.
• Overall coverage increased (+0.2%) to 76.531%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
internal/store/postgres/grant_repository.go	14	21	66.67%
<!--	Total:	14	21

Files with Coverage Reduction	New Missed Lines	%
internal/store/postgres/grant_repository.go	1	85.84%
internal/store/postgres/approval_repository.go	4	88.1%
internal/store/postgres/policy_repository.go	5	78.85%
internal/store/postgres/resource_repository.go	7	87.59%
internal/store/postgres/provider_repository.go	8	85.48%
internal/store/postgres/appeal_repository.go	9	89.26%
<!--	Total:	34

Totals
Change from base Build 3176046106:	0.2%
Covered Lines:	5886
Relevant Lines:	7691

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💛 - Coveralls