Refactoring the truncate method to not do a sort-circuit return

Truncate now has the ability to receive a html option that allows it to call rails helpers.

This way if my text is long I don't have to do something like this:

.text
= truncate(@text, :length => 27)

 if @text.size >= 27
    = link_to "continue", notes_path, ....."")

This guide is currently a wip and pending reviews. [ci skip]

installs only the gems that are already in the gemfile

[ci skip]

[guides] Update rails on rack

[getting started] Update Setting the Application Home Page to show the generated get "welcome/index" route

This is fairly common in Rails applications and is requested a lot of the time on Stack Overflow and #rubyonrails

Reset postgreSQL search path in db:test:clone_structure.

Reorder deep_symbolize_keys methods

Remove prepared statement from system query in postgresql adapter

Maximum wait_timeout on Windows is 2147483

Fix Range#sum optimized version

At 1bd4d1c6 was added Range#sum
optimized version for arithmetic progressions. This improvment injected
a defect with not integer range boundaries. The defect was fixed by
e0adfa82. The second commit really
disabled optimization at all because in Ruby integer-valued numbers are
instances of Fixnum and Bignum classes. We should #use is_a?
(#kind_of?) method instead #instance_of? to check if value is numerical:

    1.class                 # => Fixnum
    1.instance_of?(Integer) # => false
    1.is_a?(Integer)        # => true

    -100_000_000_000.class                 # => Bignum
    -100_000_000_000.instance_of?(Integer) # => false
    -100_000_000_000.is_a?(Integer)        # => true

Moreover original implementation of Range#sum has a defect with reverse
range boundaries. If the first boundary is less than the second range is
empty. Current commit fixes and tests this case too.

Unnecessary peace of text was injected at
507da04a by mistake.

Examples should be not square to visually underline a difference between
Array#in_groups and Array#in_groups_of.

add `self.` to allow method name using ruby keyword

Fixes build 4008.1

This fixex build 4008.1[1] because of the changes made in

4001835d

[1] http://travis-ci.org/#!/rails/rails/jobs/1429671