Move `nobody` position in `UserRole` magic number to constant (#29465)

app/models/user_role.rb

@@ -39,6 +39,7 @@ class UserRole < ApplicationRecord
   }.freeze
 
   EVERYONE_ROLE_ID = -99
+  NOBODY_POSITION = -1
 
   module Flags
     NONE = 0
@@ -104,7 +105,7 @@ class UserRole < ApplicationRecord
   has_many :users, inverse_of: :role, foreign_key: 'role_id', dependent: :nullify
 
   def self.nobody
-    @nobody ||= UserRole.new(permissions: Flags::NONE, position: -1)
+    @nobody ||= UserRole.new(permissions: Flags::NONE, position: NOBODY_POSITION)
   end
 
   def self.everyone
@@ -173,7 +174,7 @@ class UserRole < ApplicationRecord
   end
 
   def set_position
-    self.position = -1 if everyone?
+    self.position = NOBODY_POSITION if everyone?
   end
 
   def validate_own_role_edition

spec/models/user_role_spec.rb

@@ -139,7 +139,7 @@ RSpec.describe UserRole do
     end
 
     it 'has negative position' do
-      expect(subject.position).to eq(-1)
+      expect(subject.position).to eq(described_class::NOBODY_POSITION)
     end
   end
 
@@ -159,7 +159,7 @@ RSpec.describe UserRole do
     end
 
     it 'has negative position' do
-      expect(subject.position).to eq(-1)
+      expect(subject.position).to eq(described_class::NOBODY_POSITION)
     end
   end