Implementation
Merge branch 'master' into #589
Issue 532: initial commit
Rewrote with MkStorage
Merge branch 'master' into #589

Conflicts:
	src/main/java/com/jcabi/github/mock/MkRepoCommit.java
Issue 532: code review and merge changes
Fixed compile errors
Added @NotNull annotations
Merge pull request #648 from sanai56967/532

#648: pull request Issue 532: initial commit
Merge pull request #624 from cyberone/#589

#624: pull request #589