Updated guides with latest method [ci skip]

for blank?
fixed file name references [ci skip]
Updated guides with latest method [ci skip]
Removed doc of removed method diff [ci skip]
Fix the SQLite gem name
Add packages list for ArchLinux [ci skip]

Add the packages required on Arch Linux when setting up the development
dependencies
grab executable from rubygems

As done here d7fc97d3f90c0e30865d32ce202658f03248cacc
Revert "Fix the SQLite gem name"

This reverts commit 700c6c65bcce17d4c61423ceaef031bcbe203337.

Bot the `sqlite3` and `sqlite3-ruby` gems exist.
https://rubygems.org/gems/sqlite3
https://rubygems.org/gems/sqlite3-ruby

In fact, they both point to the same github repository.
https://github.com/luislavena/sqlite3-ruby

However, the last one hasn't been released since 2011, while the first
one keeps getting regular releases.
Refix my misreading of the diff

sorry @robin850.
Thanks @fxn
Add a SQL example for `not` [ci skip]

To share a certain logic across other examples, let's add a sample SQL
code generated by the given Ruby code
Use hyphenated version of assert_url [ci skip]
Fixes typo in Object#try!
Update of 'The Asset Pipeline' guide for Rails 4. [ci skip]
Minor refactor - Uses Enumerable#to_a instead of iterate and add to an
array
Merge pull request #11625 from phstc/minor-refactor-code-gardener-grouping

Minor refactor - Uses Enumerable#to_a instead of iterate and add to an array
fix order dependent test

`ReflectionTest` uses column information in tests and those tests break
if tests are run in random order.
fix order dependent test related to migration

If the order in which tests are executed is changed then test fails.
This commit ensures that all migrations are run before ensuring that
there are no pending migration.
Merge pull request #11633 from neerajdotname/fix_rder_dependent_test

fix order dependent test
make test order independent by resetting timezone
Fix lixml2 to libxml2 [ci skip]