$ sudo apt-get remove ruby-bson 

Uninstall ruby-bson including dependent package

If you would like to remove ruby-bson and it's dependent packages which are no longer needed from Ubuntu,

$ sudo apt-get remove --auto-remove ruby-bson 

Use Purging ruby-bson

If you use with purge options to ruby-bson package all the configuration and dependent packages will be removed.

$ sudo apt-get purge ruby-bson 

If you use purge options along with auto remove, will be removed everything regarding the package, It's really useful when you want to reinstall again.

$ sudo apt-get purge --auto-remove ruby-bson 

See Also,