* move create issue comment to comments package

* extract actions on update/delete comment from models to comment service

* fix lint

* fix lint

* Fix assets key on release webhook

* Fix assets key on release webhook

* Add message to log on AddReleaseAttachments failure

* move all mail related codes from models to modules/mailer

* fix lint

* use DBContext instead Engine

* use WithContext not WithEngine

* Use DBContext instead of Engine

* don't use defer when sess.Close()

* move DBContext to context.go and add some methods

* move mailer from modules/ to services

* fix lint

* fix tests

* fix fmt

* add gitea copyright

* fix tests

* don't expose db functions

* make code clear

* add DefaultDBContext

* fix build

* fix bug

* move create release from models to a standalone package

* fix lint

* fix comment year

* fix lint

* fix lint

* fix package import name

* fix vendor

* fix go mod

* some refactors

* fix vendor

* use go1.12 make vendor

* fix vendor

* move git diff codes from models to services/gitdiff

* fix template

* fix test

* fix template