ActiveRecord where field = ? array of possible values

From here it appears to be done using an SQL in statement:

Model.where('id IN (?)', [array of values])

Or more simply, as kdeisz pointed out (Using Arel to create the SQL query):

Model.where(id: [array of values])

From the ActiveRecord Query Interface guide

If you want to find records using the IN expression you can pass an array to the conditions hash:

Client.where(orders_count: [1,3,5])

For readability, this can be simplified even further, to:

Model.find_by(id: [array of values])

This is equivalent to using where, but more explicit:

Model.where(id: [array of values])