This reverts commit 94c2516a, reversing
changes made to ae44e5ec.

Advanced cache

Fixes #1993

* Build missing cache values in background job after each push
* Store commit_count in project table. Refresh in background job
* moved repository size calculation in background job


## Advantages

Every time push is triggered - we build cache for project even without user visiting project page. 
That means first visit is as fast as others now. This is especially good for active projects where people have some requests fast because of cache and some slow - because cache was build in their request. 

Between cache expired and cache built we we had gap when Linux repo can give 502 error because calculation commits count takes 30 seconds or even more. 
Using value from database fix this problem. Before cache is updated you see old value from database. After - you see new one. 

Basically this merge request is super win to GitLab. We don't do some heavy operations in user request but instead in background job. 

## Temporary problem

After this migration all projects will have `0` commits in database. It fill be replaced with real value on next push. I did not add recalculation to migration because it will last forever on big instances.  Can be fixed by adding rake task which will go in background on live instance without downtime

See merge request !986

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

Closes #1798

delay is in seconds
more legible code in session_store
Added `GitLab restart required` help block to session_expire_delay

settings

Closes https://github.com/gitlabhq/gitlabhq/issues/6745

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

This feature was requested long ago:

http://feedback.gitlab.com/forums/176466-general/suggestions/4118466-ability-to-register-only-from-ceratain-domains

This MR is based off !253 but changed to use application settings and use wildcard strings
to give more flexibility in pattern matching. Regexps seemed overkill and easy to get wrong.

Only restrict e-mail addresses upon creation

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

Upon tagging a repository, an error due to a missing migration occurred:

```
    PG::Error: ERROR:  column "taggings_count" does not exist
        LINE 1: UPDATE "tags" SET "taggings_count" = COALESCE("taggings_coun...
```

Ran `rake acts_as_taggable_on_engine:install:migrations`, removed the first
migration that created the `tags` and `taggings` table, and added the rest.

Closes #1512
Closes https://github.com/gitlabhq/gitlabhq/issues/6867
Closes https://github.com/gitlabhq/gitlabhq/issues/9194

Add new global application settings for default project and snippet
visibility levels.

Signed-off-by: Jeroen van Baarsen <jeroenvanbaarsen@gmail.com>

This commit allows user to show one of their emails in profile page,
or don't show email in this page.

Fix bug where error messages from Dropzone would not be displayed on the issues page

Closes #1258