ActiveRecord create: pass in an array of attributes

According the documentation you can create records from an array of hashes:

The attributes parameter can be either be a Hash or an Array of Hashes. These Hashes describe the attributes on the objects that are to be created.

 MyModel.create([{attr_1: some_attr, attr_2: 4}, {attr_1: some_attr, attr_2: 5}])

At the time the question was asked ActiveRecord did not have any built-in features to efficiently insert multiple records at once. As of today Rails 6 is the current stable release and it comes with Model#insert_all! which is a method for bulk inserting.

You'll find the documentation for it here https://edgeapi.rubyonrails.org/classes/ActiveRecord/Persistence/ClassMethods.html#method-i-insert_all-21

It is worth to mention that Rails 6 also implements Model#upsert_all! which efficiently inserts or updates in case the the record exists.