Performance is improved in two steps:

1. On PostgreSQL an expression index is used for checking lower(email)
   and lower(username).
2. The check to determine if we're searching for a username or Email is
   moved to Ruby. Thanks to @haynes for suggesting and writing the
   initial implementation of this.

Moving the check to Ruby makes this method an additional 1.5 times
faster compared to doing the check in the SQL query.

With performance being improved I've now also tweaked the amount of
iterations required by the User.by_login benchmark. This method now runs
between 900 and 1000 iterations per second.

This simplifies the "Report button" to not use open a dropdown and
adds a tooltip on this button.
This also removes an extra spec and adds missing specs.

Closes #2662

Only show recent push event if the branch still exists or a recent merge request has not been created

Closes #2277

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

This method encapsulates all the logic for disabling 2FA on a specific
User model.

- Removes looking up authors/committers by name
- Renames `User.find_for_commit` to `User.find_by_any_email`

Now it executes a single query instead of a possible three at the cost
of some scary-looking ARel calls.

Closes https://github.com/gitlabhq/gitlabhq/issues/9328

To prevent loose of group data you need to transfer or remove group
first before you can remove user
Signed-off-by: NDmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

**What does this do?**
It removes the very strict sanitation on the users bio field, so that people can
have a bio like "I <3 GitLab"

**Why is this needed?**
Currently when you enter a bio with "I <3 GitLab", we only store "I ". This is
unexpected behaviour, since we want users to have a normal profile, without
having to worry what characters are allowed and which are not.

**Related issues:**
Fixes https://github.com/gitlabhq/gitlabhq/issues/5625Signed-off-by: NJeroen van Baarsen <jeroenvanbaarsen@gmail.com>

Now there is a single source of information for which attribute a model
uses to be referenced, and its special character.