You may be working on different projects and each one using different gemset with rvm. You generally follow below steps on terminal to set correct gemset for your project.
$ rvm list #will list all the installed rubies, only one in my case
=* ruby-1.9.3-p194 [ i686 ]
$ rvm use ruby-1.9.3-p194 #set the ruby version
$ rvm gemset create thirdpillar #create a gemset if not already there
$ rvm gemset list # it list all the gemset within the selected ruby
gemsets for ruby-1.9.3-p194 (found in /home/arun/.rvm/gems/ruby-1.9.3-p194)
$ rvm gemset use thirdpillar # It will sete thirdpillar gemset for my project say myproject
what if I want to skip typing these every time, and want to automatically load the correct rvm and gemset for my project whenever I cd to myproject on the terminal. This can be done by adding .rvmrc file to your project folder. and adding just one line to it as below
Example: for the ruby and gemset we have selected above , the line will be
rvm ruby-1.9.3-p194@thirdpillar # If you have any doubt about the complete name of gemset to use, go to .rvm folder -> then click gems folder, there you will find one folder for every gemset you have created, just copy the name of folder you want to use.
Now, when you go to terminal and cd to your project, the correct ruby and gemset will be automatically loaded
$ cd myproject
myproject$ #thus you moved to myproject folder which will load the gemset automatically
NOTE : do not commit .rvmrc to git as, other your other team mate may have created gemset with different name. So better to add .rvmrc to .gitignore file, so that it should not be commited by even mistake