Modified schema via migrations.
Added one-to-one relationship between the two models.
Added changelog file

These counts significantly increase the load time for these
requests. Users can now opt in to receiving the counts by setting
`with_counts=true` in requests. This is a breaking change, but hopefully
a fairly minor one.

Add released_at field to releases API
Add released_at column to releases table
Return releases to the API sorted by released_at

Closes https://gitlab.com/gitlab-org/gitlab-ce/issues/50813

Cleanup IssueBasic entity to keep it basic and move extra attributes
to Issue entity which contains more details

When issues_controller endpoint was used for search, the parameters
passed to the controller were slightly different then the ones
passed to API. Because the searchbar UI is reused in different
places and builds the parameters passed to request in same way
we need to account for old parameter names.


Add issues_statistics api endpoints

Adds issue_statistics api endpoints for issue lists and returns
counts of issues for all, closed and opened states.


Expose more label attributes based on a param

When requesting issues list through API expose more attributes
for labels, like color, description if with_labels_data param is
being passed, avoiding this way to change response schema for users
that already use API.

https://gitlab.com/gitlab-org/gitlab-ce/issues/57402

This is step one of resolving
https://gitlab.com/gitlab-org/gitlab-ce/issues/56838.

Here is what changed:
- Revert the security fix from bdee9e84.
- Do not leak repository information (tag name, commit) to guests in API
responses.
- Do not include links to source code in API responses for users that do
not have download_code access.
- Show Releases in sidebar for guests.
- Do not display links to source code under Assets for users that do not
have download_code access.

GET ':id/releases/:tag_name' still do not allow guests to access
releases. This is to prevent guessing tag existence.

This is resolving https://gitlab.com/gitlab-org/gitlab-ce/issues/30157.

Implement new API endpoint `/projects/:id/environments/:environment_id`
to expose single environment. Include information for environment's last
deployment if there is one.

Backports https://gitlab.com/gitlab-org/gitlab-ee/merge_requests/10161
(code out of ee/ folder).

Expose head pipeline for the MR in the api when requesting
related merge requests for an issue and show a detailed
status for the pipeline, which would include:
details_path, favicon, group, icon, label, text, tooltip.

https://gitlab.com/gitlab-org/gitlab-ce/issues/57662#note_152023412

Signed-off-by: NRémy Coutable <remy@rymai.me>

This reverts merge request !25173

"Maintainer" will be freed to be used for #42751

This is useful for annotated tags, where the deferenced target is not the same as the tag object. At the moment there is no way to differentiate the two through the tag API.

This change adds a "target" property and leaves the existing "commit" property alone so that existing behaviour is not altered.

* adds basic discussions API for issues and snippets
* reorganizes notes specs (so same tests can be used for all noteable types - issues, MRs, snippets)