Quality gate is the approach to make transparent and semi-formal decision to go to next stage of the project or to complete the current one. Before a build will be shipped to customers team follows simple checklist:
Do we have a testable build of our great software?
Was code reviewed?
Were unit and automatic tests passed?
Was manual testing performed?
Were critical or major issues found during testing?
When you want deliver qualitative software fast you have to pass through this checklist quickly. DevOps board collects all required info to make decision fast having a glance at single screen only.