WIP: Generate system note after Task item has been updated on Issue or Merge Request. #2296

Everytime the User check or uncheck a Task Item from the Issue or Merge Request description, a new update is going to be added to the activity logs of the Issue or Merge Request.

Note that when using the edit form, you can only update the Task item status or add/delete/modify existing ones. Doing both actions is not fully supported.

@DouweM thanks for reviewing the other MRs, this is the MR that we should use from now on. I'm going to give a look at the build. Please let me know if I can do any other change in order to have this MR in good shape.

Added 30 commits:

• 66bb4f3e - Add missing dot in confirm modal
• 1318e7c2 - award emoji
• f1386ff7 - css improvements
• 27b78480 - replace emoji references from class name to data [ci skip]
• 1edd1e80 - add stats on hover
• 40df385c - award for merge requests[ci skip]
• 7b331ee9 - Emoji: refactoring
• 285c62ae - fix
• d7955987 - Emoji: fix image of emoji when it is submitted via comment
• 350f61c3 - better regexp
• dbdd0556 - improve style
• 99ea9be8 - addressing comments
• 3d588d6b - add changelog
• 2506ed5c - fix schema
• de1b5a97 - satisfy rubocop
• 8ade0276 - Improve UI for emoji awards
• 5b60d70e - Few minor improvements to emoji awards UI
• e4bb20d8 - Added index on issues.state
• 499cc73b - Added index on projects.visibility_level
• 2b56e65f - Updated DB schema with new issues/projects indexes
• 3c384784 - Added benchmark for IssuesFinder
• 01bc01af - Removed trailing whitespace from IssuableFinder
• f522f981 - Memoize IssuableFinder#projects
• e3a85f50 - Use a JOIN in IssuableFinder#by_project
• 91f58872 - Changelog entry for finding issues performance
• c91cd057 - added spinach tests
• a6613958 - added specs
• fa4bf371 - Align hash literals in IssuesFinder spec
• 75f685c8 - adressing comments
• 431c8df5 - fox tests

Added 40 commits:

• 431c8df5...0383f84d - 39 commits from branch master
• 4865a137 - Merge branch 'master' into todo_system_notes

@DouweM I'm a bit concerned about integrating my changes into master and the possibility of rewriting master's history, this is due to I've been pulling master into my branch with the rebase option. Can you please let me know if I should create a new branch and open a new MR instead?

by the way, the next time that I see conflicts in the MR I'm going to merge the target branch instead of pulling with rebase.

@DouweM sorry for all this confusion, I will definitely be more careful for the next time. I have created a more cleaner MR: https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/1848

Feel free to close this MR if it is no longer required.

Replaced by !1848 (merged)

Status changed to closed

@rdavila To give you some peace of mind: master is a protected branch, so whatever you do locally, anything you try to push there will be rejected. You can rebase your own branch on master safely, this will only rewrite the history of your own branch, which is safe. In any case, you should never need to create new MR, you can always force-push to your own feature branch (todo_system_notes in this case) and the MR will be updated.