Merge branch 'tasks' into 'master'

Add Todos

Closes #2425

Tasks:

-  Prepare database
 - [X] Create a new table (`todos`)
- Tasks Queue view
 - [X] Add a number icon showing the number of todos on the top right next to the new and logout button that will redirect the user to the todos page
 - [X] Add a chronological list of todos, with the 'Todos' tab active by default
 - [X] Add a 'Done' button to each todo
 - [x] Add filters (project, author, type, and action)
- Todos generation
 - [X] When user issue/mr is assgined to someone
 - [x] When user is mentioned on (issues/mr's/comments)
- Mark todo as `done`
 - [X] When clicks on the 'Done' button
 - [X] When edit issue/mr
 - [X] When left/edit a comment
 - [X] When reassign issue/mr
 - [X] When add/remove labels to issue/mr
 - [X] When issue/mr is closed
 - [X] When mr is merged
 - [X] When added an emoji
 - [X] When changed the issue/mr milestone

* Screenshot:

![Screenshot_2016-02-20_12.45.57](/uploads/4b2554b1bde25aed3347e1ae41e8e0c0/Screenshot_2016-02-20_12.45.57.png)

See merge request !2817
Status Job ID Name Coverage
  Test
passed #732985
ruby mysql
brakeman

00:06:18

failed #732988
ruby mysql allowed to fail
bundler:audit

00:04:34

passed #732987
ruby mysql
flay

00:06:27

passed #732986
ruby mysql
flog

00:10:39

passed #732984
ruby mysql
rubocop

00:06:53

passed #732974
ruby mysql
spec:api

00:14:18

passed #732990
ruby mysql
spec:api:ruby22

00:21:46

failed #732978
ruby mysql allowed to fail
spec:benchmark

00:06:40

failed #732994
ruby mysql allowed to fail
spec:benchmark:ruby22

00:11:49

passed #732973
ruby mysql
spec:feature

00:18:03

passed #732989
ruby mysql
spec:feature:ruby22

00:30:17

passed #732976
ruby mysql
spec:lib

00:11:06

passed #732992
ruby mysql
spec:lib:ruby22

00:22:49

passed #732975
ruby mysql
spec:models

00:17:54

passed #732991
ruby mysql
spec:models:ruby22

00:29:50

passed #732979
ruby mysql
spec:other

00:10:51

passed #733849
mysql ruby
spec:other:ruby22

00:11:04

passed #732977
ruby mysql
spec:services

00:24:01

passed #732993
ruby mysql
spec:services:ruby22

00:41:18

passed #732982
ruby mysql
spinach:other

00:17:45

passed #732998
ruby mysql
spinach:other:ruby22

01:08:26

passed #732980
ruby mysql
spinach:project:half

00:28:37

passed #733848
mysql ruby
spinach:project:half:ruby22

00:20:26

passed #732981
ruby mysql
spinach:project:rest

00:39:30

passed #732997
ruby mysql
spinach:project:rest:ruby22

00:37:51

passed #732983
ruby mysql
teaspoon

00:02:57

failed #732995
ruby mysql
spec:other:ruby22

00:22:23

failed #732996
ruby mysql
spinach:project:half:ruby22

00:32:44

 
Name Stage Failure
failed
spec:benchmark:ruby22 Test There is an unknown failure, please try again
/builds/gitlab-org/gitlab-ce/lib/tasks/spinach.rake:54:in `block in run_commands'
/builds/gitlab-org/gitlab-ce/lib/tasks/spinach.rake:53:in `each'
/builds/gitlab-org/gitlab-ce/lib/tasks/spinach.rake:53:in `run_commands'
/builds/gitlab-org/gitlab-ce/lib/tasks/spec.rake:55:in `block (2 levels) in <top (required)>'
Tasks: TOP => spec:benchmark
(See full trace by running task with --trace)
D, [2016-02-22T02:48:41.953505 #1026] DEBUG -- : ** [Raven] Event not sent due to excluded environment: test

ERROR: Build failed with: exit code 1
failed
bundler:audit Test There is an unknown failure, please try again
Advisory: CVE-2012-6684
Criticality: Medium
URL: http://www.osvdb.org/show/osvdb/115941
Title: RedCloth Gem for Ruby Textile Link Parsing XSS
Solution: remove or disable this gem until a patch is available!

Vulnerabilities found!

ERROR: Build failed with: exit code 1
failed
spec:benchmark Test There is an unknown failure, please try again
/builds/gitlab-org/gitlab-ce/lib/tasks/spinach.rake:54:in `block in run_commands'
/builds/gitlab-org/gitlab-ce/lib/tasks/spinach.rake:53:in `each'
/builds/gitlab-org/gitlab-ce/lib/tasks/spinach.rake:53:in `run_commands'
/builds/gitlab-org/gitlab-ce/lib/tasks/spec.rake:55:in `block (2 levels) in <top (required)>'
Tasks: TOP => spec:benchmark
(See full trace by running task with --trace)
D, [2016-02-22T02:43:56.110869 #1066] DEBUG -- : ** [Raven] Event not sent due to excluded environment: test

ERROR: Build failed with: exit code 1