How do I create database tables for a craft cms plugin on install?
PluginNameRecord.php is how Craft installs database tables. You can also have multiple tables by using PluginName_TableRecord.php where 'Table' will be the name of the new table in the database.

Might also be worthwhile to mention that the cocktails recipe you linked to has a lot of issues as it has not been updated for the latest versions of Craft. 

Sean Delaney updated that plugin and the new repository is here: 

https://github.com/seandelaney/cocktailrecipes