* Sync releases table with tags on push and for mirrors
* Code style fixes
* Fix api to return only releases
* Optimize release creation and update
Minimize posibility of race conditions
* Fix release lower tag name updating
* handle tag reference update by addionally comparing commit id
* Moved attachaments POST url from /issues/attachments to /attachments
* Implemented attachment upload on release page
* Implemented downloading attachments on the release page
* Added zip and gzip files to default allowed attachments
* Implemented uploading attachments on edit release
* Renamed UploadIssueAttachment to UploadAttachment