rails 5 collection select

I am trying to make a collection_select that I get a drop down with the values of a field from another model. I got the following 2 models:

Documents:

class CreateDocuments < ActiveRecord::Migration[5.0]
  def change
    create_table :documents do |t|
      t.string :etiquette_number
      t.string :etiquette_type
      t.boolean :important
      t.string :work_text
      t.integer :user_id


      t.timestamps
    end
  end
end

Entries:

class CreateEntries < ActiveRecord::Migration[5.0]
  def change
    create_table :entries do |t|
      t.integer :document_id
      t.integer :user_id
      t.string :work
      t.date :date
      t.integer :time

      t.timestamps
    end
  end
end

I want to get a dropdown select on document_id (in Entries model), where I can select the values of the id of a document.

I got this so far but I am not sure if it is the right way

models/document.rb

class Document < ApplicationRecord
  has_many :Entries
end

models/entry.rb

class Entry < ApplicationRecord
  belongs_to :Documents
end

I really hope that someone can help me and as you see in the title I am using Rails 5.

class Document < ApplicationRecord
 has_many :entries
end


class Entry < ApplicationRecord
 belongs_to :document
end

In your view file like: new.html.erb

 <%= f.select :document_id, Document.all.collect { |p| p.id }, include_blank: true %>