Remove unnecessary require from active_support/inflector/methods.rb

`active_support/inflections` already requires
`active_support/inflector/inflections`. There's no need to require it in
`active_support/inflector/methods`.
Use Range#cover? for Numeric ranges (tests via endpoints) and use Range#include? for non-numeric ranges

added changelog message
Added a warning about #1769 to the routing guide.
Use symbols instead of strings

ActiveSupport::Concern is used all over Rails
This PR will only create 3 new objects as keys are never recreated and
are not subject to garbage collection.

The strings were being uniquely created and garbage collected. I don't
have any performance numbers but this should be better than all of the
GC.
Merge pull request #142 from codyrobbins/master

Added a warning about #1769 to the routing guide
more guidelines for command line
`existant` => `existent`
replace version 3.2.3 by 4.0.0.beta in command line
`dasboard` => `dashboard`
date_field docs for action view
Change "." to ":" for formatting purpose
Merge pull request #151 from vatrai/action_view_basic

date_field docs for action view
Merge pull request #146 from vatrai/command_line_rake_guid

more guidelines for rake tasks
Merge pull request #150 from vatrai/edgerails_in_command_line

replace version 3.2.3 by 4.0.0.beta in command line
Change documentation about contributing to Docs
Update contributing to rails guide to depict new contributing to documentation info
reword the docrails info [ci skip]
Use markdown quotes instead <tt> tag
fix quotes and ruby old hashes
reorder finder methods list alphabetically