Installed ruby on rails on ubuntu using RVM doesn't work anymore

i installed the ruby on rails on Ubuntu using RVM after installation,i tested like this rails -v it i get rails version and also checked ruby -v and also get version result but after i close the terminal. and open another terminal it gives me the following error when i ask for ruby or rails version:

The program 'rails' is currently not installed. You can install it by typing:
sudo apt install ruby-railties