Associate managers group to StagingWorkflow

Every staging workflow now have a group of managers that can work on
them.

src/api/app/models/group.rb

@@ -5,6 +5,7 @@
 # Groups have an arbitrary number of roles and users assigned to them.
 #
 class Group < ApplicationRecord
+  has_one :staging_workflow, class_name: 'Staging::Workflow', foreign_key: :managers_group_id, dependent: :nullify
   has_many :groups_users, inverse_of: :group, dependent: :destroy
   has_many :users, -> { distinct }, through: :groups_users
   has_many :group_maintainers, inverse_of: :group, dependent: :destroy

src/api/app/models/staging/workflow.rb

@@ -6,6 +6,8 @@ def self.table_name_prefix
   include CanRenderModel
 
   belongs_to :project, inverse_of: :staging
+  belongs_to :managers, class_name: 'Group'
+
   has_many :staging_projects, class_name: 'Staging::StagingProject', inverse_of: :staging_workflow, dependent: :nullify,
                               foreign_key: 'staging_workflow_id' do
     def without_staged_requests
@@ -25,6 +27,8 @@ def ready_to_stage
 
   has_many :staged_requests, class_name: 'BsRequest', through: :staging_projects
 
+  validates :managers, presence: true
+
   after_create :create_staging_projects
 
   def unassigned_requests

src/api/db/migrate/20181113095753_add_staging_managers_group.rb

@@ -0,0 +1,7 @@
+class AddStagingManagersGroup < ActiveRecord::Migration[5.2]
+  def change
+    change_table :staging_workflows do |t|
+      t.references :managers_group, index: true, type: :integer
+    end
+  end
+end

src/api/db/structure.sql

@@ -1147,8 +1147,10 @@ CREATE TABLE `staging_workflows` (
   `project_id` int(11) DEFAULT NULL,
   `created_at` datetime NOT NULL,
   `updated_at` datetime NOT NULL,
+  `managers_group_id` int(11) DEFAULT NULL,
   PRIMARY KEY (`id`),
-  UNIQUE KEY `index_staging_workflows_on_project_id` (`project_id`)
+  UNIQUE KEY `index_staging_workflows_on_project_id` (`project_id`),
+  KEY `index_staging_workflows_on_managers_group_id` (`managers_group_id`)
 ) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci;
 
 CREATE TABLE `static_permissions` (
@@ -1423,6 +1425,7 @@ INSERT INTO `schema_migrations` (version) VALUES
 ('20180924135535'),
 ('20181008150453'),
 ('20181016103905'),
-('20181025152009');
+('20181025152009'),
+('20181113095753');