To install sqlite3 gem we need to install development package for ruby and sqlite3 it self because of the need to compile gem native extension.
On ubuntu/mint/debian do as follow :
apt-get install ruby-dev
apt-get install libsqlite3-dev
Dont forget to execute as root.
After that we can execute gem install sqlite3.
Thats all … Bye.
Happy chinesse new year 2570 !