title: FactoryBot unique constraint violation error, when specifying id in the factory
body: <p>When a record is created with specified id, subsequent create call fails with unique constraint violation error.</p>
  
  <pre><code>Output:
  
  [1]&gt; create(:user, id: 1)
  =&gt; #&lt;User:0x00005615116f7378id: 1,created_at: Thu, 23 Apr 2020 08:21:04 CEST +02:00,updated_at: Thu, 23 Apr 2020 08:21:04 CEST +02:00...
  
  [2]&gt; create(:user)
  ActiveRecord::RecordNotUnique: PG::UniqueViolation: ERROR:  duplicate key value violates unique constraint "users_pkey"DETAIL:  Key (id)=(1) already exists.
  </code></pre>
  
  <p>I would expect FactoryBot to pick up from the last created id and continue on creating. :) What am I missing here? Please advise. </p>
  
  <p>FactoryBot version(as taken from the Gemfile):<br>
  factory_bot_rails (5.1.1)<br>
  factory_bot (5.1.2)  </p>
  
  <p>[edit]</p>
  
  <p>spec/factories/users.rb</p>
  
  <pre class="lang-rb prettyprint-override"><code>FactoryBot.define do
    factory :user do
      first_name { "Max" }
      last_name { "Mustermann" }
      email_addresses { build_list(:email_address, 1) }
      password { TEST_USER_PASSWORD }
      accepted_terms_of_use { true }
    end
  end
  </code></pre>
  
  <p>from db/schema.rb</p>
  
  <pre class="lang-rb prettyprint-override"><code>create_table "users", id: :serial, force: :cascade do |t|
    t.string "first_name", limit: 255
    t.string "last_name", limit: 255
    t.string "password_digest", limit: 255
    t.boolean "accepted_terms_of_use", default: false, null: false
  end
  
  add_foreign_key "email_addresses", "users"
  </code></pre>