Cant install rails 4.0 using rubyinstaller. *** extconf.rb failed *** - ruby

Question

I am trying to install ruby on rails (v4.0) using ruby installer. It is throwing me this error. I am brand new to RoR and some websites told me to install devkit. I have done that. I ran gem install thin
C:\Users\shashid\Downloads>gem install rails
Temporarily enhancing PATH to include DevKit...
Building native extensions. This could take a while...
ERROR: Error installing rails:
ERROR: Failed to build gem native extension.
C:/RubyRails/bin/ruby.exe extconf.rb
*** extconf.rb failed ***
Could not create Makefile due to some reason, probably lack of necessary
libraries and/or headers. Check the mkmf.log file for more details. You may
need configuration options.
Provided configuration options:
--with-opt-dir
--without-opt-dir
--with-opt-include
--without-opt-include=${opt-dir}/include
--with-opt-lib
--without-opt-lib=${opt-dir}/lib
--with-make-prog
--without-make-prog
--srcdir=.
--curdir
--ruby=C:/RubyRails/bin/ruby
--with-atomic_reference-dir
--without-atomic_reference-dir
--with-atomic_reference-include
--without-atomic_reference-include=${atomic_reference-dir}/include
--with-atomic_reference-lib
--without-atomic_reference-lib=${atomic_reference-dir}/
C:/RubyRails/lib/ruby/2.0.0/mkmf.rb:431:in `try_do': The compiler failed to gene
rate an executable file. (RuntimeError)
You have to install development tools first.
from C:/RubyRails/lib/ruby/2.0.0/mkmf.rb:516:in `try_link0'
from C:/RubyRails/lib/ruby/2.0.0/mkmf.rb:814:in `try_run'
from extconf.rb:22:in `<main>'
Gem files will remain installed in C:/RubyRails/lib/ruby/gems/2.0.0/gems/atomic-
1.1.10 for inspection.
Results logged to C:/RubyRails/lib/ruby/gems/2.0.0/gems/atomic-1.1.10/ext/gem_ma
ke.out
Thank you in advance for your help

Answer 1

You need to install Ruby DevKit if on windows, get it from: http://rubyinstaller.org/downloads/ (scroll down a little).

Answer 2

Same story here deleting ruby and installing:
Ruby 2.0.0-p247
DevKit-mingw64-32-4.7.2-20130224-1151-sfx.exe
from http://rubyinstaller.org/downloads/ solved the problem.

Answer 3

Try to use railsinstaller from http://railsinstaller.org/
it will install follwing
Ruby 1.9.3-p392
Rails 4
Bundler
Git
Sqlite
TinyTDS
SQL Server Support
DevKit

Answer 4

The same can happen when you try to combine 32-bit Ruby and 64-bit DevKit.
The solution is to use same-bit versions.
For instance current versions:
rubyinstaller-2.0.0-p247-x64.exe
DevKit-mingw64-64-4.7.2-20130224-1432-sfx.exe