refs https://github.com/TryGhost/Product/issues/3818
- added a check to compare hostname and pathnames of URLs. Different
subdomain or different pathname = different URLs, but protocol, www,
query parameters and hash fragments are ignored.
closes https://github.com/TryGhost/Product/issues/3818
- instead of fetching all recommendations and matching URLs on the frontend, we now query the database directly to find an existing Recommendation by URL. When comparing URLs, we don't take into account the protocol, www, query parameters nor hash fragments
closes https://github.com/TryGhost/Product/issues/3818
- in Admin, when adding a recommendation, the URL is compared against all existing ones. If the URL is already recommended, the publisher is shown an error: "A recommendation with this URL already exists.". Protocol, www, query parameters and hash fragments are ignored during the URL comparison.
- on the backend, there is another uniqueness validation for the recommendation URL. This check is redundant when adding a recommendation from Admin, but helps to keep data integrity when recommendations are added through other paths (e.g. via the API)
