No such file to load / Missing these required gems - ruby-on-rails

Question

I have an issue with a "missing gem".
After executing rake gems:install
>> rake gems:install
(in /some/path)
gem install google-api-client --version "= 0.7.1"
Successfully installed uuidtools-2.1.5
Successfully installed google-api-client-0.7.1
2 gems installed
Installing ri documentation for uuidtools-2.1.5...
Installing ri documentation for google-api-client-0.7.1...
Installing RDoc documentation for uuidtools-2.1.5...
Installing RDoc documentation for google-api-client-0.7.1...
Where we can see with a gem list the presence of the gem
>> gem list | grep google
google-api-client (0.7.1)
When starting my rail app I get a :
Missing these required gems:
google-api-client
You're running:
ruby 1.8.7.302 at /usr/bin/ruby1.8
rubygems 1.3.7 at /some/path/.gem/ruby/1.8, /usr/lib/ruby/gems/1.8
and then Rails advices me to execute a "rake gems:install" to solve the issue..
I only have a single version of ruby installed : ruby 1.8.7-p302
>> which ruby
/usr/bin/ruby
>> ls -l /usr/bin/ruby
lrwxrwxrwx 1 root root 7 Aug 26 2013 /usr/bin/ruby -> ruby1.8
>> ruby -v
ruby 1.8.7 (2010-08-16 patchlevel 302) [x86_64-linux]
>> gem env
RubyGems Environment:
- RUBYGEMS VERSION: 1.3.7
- RUBY VERSION: 1.8.7 (2010-08-16 patchlevel 302) [x86_64-linux]
- INSTALLATION DIRECTORY: /usr/lib/ruby/gems/1.8
- RUBY EXECUTABLE: /usr/bin/ruby1.8
- EXECUTABLE DIRECTORY: /usr/bin
- RUBYGEMS PLATFORMS:
- ruby
- x86_64-linux
- GEM PATHS:
- /usr/lib/ruby/gems/1.8
- /root/.gem/ruby/1.8
- GEM CONFIGURATION:
- :update_sources => true
- :verbose => true
- :benchmark => false
- :backtrace => false
- :bulk_threshold => 1000
- REMOTE SOURCES:
- http://rubygems.org/
I don't know where does the issue come from.
(Similarly, if I just make a ruby test file
require "rubygems"
require "google-api-client"
It outputs the same error :
>> ruby test.rb
/usr/local/lib/site_ruby/1.8/rubygems/custom_require.rb:31:in `gem_original_require': no such file to load -- google-api-client (LoadError)
from /usr/local/lib/site_ruby/1.8/rubygems/custom_require.rb:31:in `require'
from test.rb:2
)
EDIT : I don't use bundle on this app.
Do you have some clue to solve this ?
Thanks !

Answer 1

Well, it was just the require that was erroneous
require "google/api_client"
instead of
require "google-api-client"
Thanks for the help.

Answer 2

You will update bundle version and then update gem.