Where to place classes in a Rails project?

Question

Ruby on Rails

I want to write a class with methods for further use in actions, helpers, etc.
Where should these classes be placed in a Rails project?

best = Best.new
best.method

PS The question may be moronic, but restrain yourself. Just write the directory please :)

Answer 1

app/controllers/concerns, google for one thing about what concern is (in short: just modules)