User belongs to Signal::User

app/models/user.rb

@@ -1,5 +1,5 @@
 class User < ApplicationRecord
-  include Accessor, ActionText::Attachable, Assignee, Mentionable, Named, Role, Transferable
+  include Accessor, ActionText::Attachable, Assignee, Mentionable, Named, Role, SignalUser, Transferable
   include Timelined # Depends on Accessor
 
   has_one_attached :avatar

app/models/user/signal_user.rb

@@ -0,0 +1,7 @@
+module User::SignalUser
+  extend ActiveSupport::Concern
+
+  included do
+    belongs_to :signal_user, dependent: :destroy, class_name: "SignalId::User", optional: true
+  end
+end

db/migrate/20250612163028_add_signal_user_id_to_users.rb

@@ -0,0 +1,6 @@
+class AddSignalUserIdToUsers < ActiveRecord::Migration[8.1]
+  def change
+    add_column :users, :signal_user_id, :integer
+    add_index :users, :signal_user_id, unique: true
+  end
+end

db/schema.rb

@@ -10,7 +10,7 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema[8.1].define(version: 2025_06_11_203906) do
+ActiveRecord::Schema[8.1].define(version: 2025_06_12_163028) do
   create_table "accesses", force: :cascade do |t|
     t.integer "collection_id", null: false
     t.datetime "created_at", null: false
@@ -336,9 +336,11 @@ ActiveRecord::Schema[8.1].define(version: 2025_06_11_203906) do
     t.string "name", null: false
     t.string "password_digest"
     t.string "role", default: "member", null: false
+    t.integer "signal_user_id"
     t.datetime "updated_at", null: false
     t.index ["email_address"], name: "index_users_on_email_address", unique: true
     t.index ["role"], name: "index_users_on_role"
+    t.index ["signal_user_id"], name: "index_users_on_signal_user_id", unique: true
   end
 
   create_table "watches", force: :cascade do |t|

db/schema_cache.yml

@@ -993,6 +993,16 @@ columns:
     default_function:
     collation:
     comment:
+  - !ruby/object:ActiveRecord::ConnectionAdapters::SQLite3::Column
+    auto_increment:
+    name: signal_user_id
+    cast_type: *1
+    sql_type_metadata: *2
+    'null': true
+    default:
+    default_function:
+    collation:
+    comment:
   - *9
   watches:
   - *22
@@ -2276,6 +2286,22 @@ indexes:
     nulls_not_distinct:
     comment:
     valid: true
+  - !ruby/object:ActiveRecord::ConnectionAdapters::IndexDefinition
+    table: users
+    name: index_users_on_signal_user_id
+    unique: true
+    columns:
+    - signal_user_id
+    lengths: {}
+    orders: {}
+    opclasses: {}
+    where:
+    type:
+    using:
+    include:
+    nulls_not_distinct:
+    comment:
+    valid: true
   watches:
   - !ruby/object:ActiveRecord::ConnectionAdapters::IndexDefinition
     table: watches
@@ -2327,4 +2353,4 @@ indexes:
     comment:
     valid: true
   workflows: []
-version: 20250611203906
+version: 20250612163028

test/fixtures/users.yml

@@ -5,18 +5,21 @@ david:
   email_address: david@37signals.com
   password_digest: <%= digest %>
   role: member
+  signal_user: 37s_fizzy_david
 
 jz:
   name: JZ
   email_address: jz@37signals.com
   password_digest: <%= digest %>
   role: member
+  signal_user: 37s_fizzy_jz
 
 kevin:
   name: Kevin
   email_address: kevin@37signals.com
   password_digest: <%= digest %>
   role: admin
+  signal_user: 37s_fizzy_kevin
 
 system:
   name: System

test/models/user/signal_user_test.rb

@@ -0,0 +1,12 @@
+require "test_helper"
+
+class User::SignalUserTest < ActiveSupport::TestCase
+  setup do
+    @user = users(:david)
+  end
+
+  test "belongs to a Signal::User" do
+    assert_not_nil @user.signal_user_id
+    assert_equal signal_users("37s_fizzy_david"), @user.signal_user
+  end
+end