Prepare db for build coverage feature

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>
Implement parsing and set coverage after build finished

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>
Show test coverage on build page and builds page

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>
Add coverage feature to changelog

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>
Merge branch 'coverage-parser' into 'master'

Coverage parser feature

Fixes #112

See merge request !73