Add migrations to wrap iterations to cadences

- create iteration_cadences table
- add association to iterations
- add migration to wrap existing iterations under cadences

db/migrate/20201228110136_create_iteration_cadence.rb

+# frozen_string_literal: true
+
+class CreateIterationCadence < ActiveRecord::Migration[6.0]
+  include Gitlab::Database::MigrationHelpers
+
+  DOWNTIME = false
+
+  disable_ddl_transaction!
+
+  def up
+    create_table_with_constraints :iteration_cadences do |t|
+      t.references :group, null: false, foreign_key: { to_table: :namespaces, on_delete: :cascade }
+      t.timestamps_with_timezone null: false
+      t.date :start_date, null: false
+      t.date :last_run_date
+      t.integer :duration_in_weeks
+      t.integer :iterations_in_advance
+      t.boolean :active, default: true, null: false
+      t.boolean :automatic, default: true, null: false
+      t.text :title, null: false
+
+      t.text_limit :title, 255
+    end
+  end
+
+  def down
+    drop_table :iteration_cadences if table_exists?(:iteration_cadences)
+  end
+end

db/migrate/20201228110238_add_iteration_cadence_to_sprints.rb

+# frozen_string_literal: true
+
+class AddIterationCadenceToSprints < ActiveRecord::Migration[6.0]
+  include Gitlab::Database::MigrationHelpers
+
+  DOWNTIME = false
+
+  disable_ddl_transaction!
+
+  INDEX_NAME = 'index_sprints_iteration_cadence_id'
+
+  def up
+    add_column :sprints, :iteration_cadence_id, :integer unless column_exists?(:sprints, :iteration_cadence_id)
+
+    add_concurrent_index :sprints, :iteration_cadence_id, name: INDEX_NAME
+    add_concurrent_foreign_key :sprints, :iteration_cadences, column: :iteration_cadence_id, on_delete: :cascade
+  end
+
+  def down
+    remove_column :sprints, :iteration_cadence_id if column_exists?(:sprints, :iteration_cadence_id)
+  end
+end

db/post_migrate/20201231133921_schedule_set_default_iteration_cadences.rb

+# frozen_string_literal: true
+
+class ScheduleSetDefaultIterationCadences < ActiveRecord::Migration[6.0]
+  include Gitlab::Database::MigrationHelpers
+
+  DOWNTIME = false
+  BATCH_SIZE = 1_000
+  DELAY_INTERVAL = 2.minutes.to_i
+  MIGRATION_CLASS = 'SetDefaultIterationCadences'
+
+  class Iteration < ActiveRecord::Base # rubocop:disable Style/Documentation
+    include EachBatch
+
+    self.table_name = 'sprints'
+  end
+
+  disable_ddl_transaction!
+
+  def up
+    Iteration.select(:group_id).distinct.each_batch(of: BATCH_SIZE, column: :group_id) do |batch, index|
+      group_ids = batch.pluck(:group_id)
+
+      migrate_in(index * DELAY_INTERVAL, MIGRATION_CLASS, group_ids)
+    end
+  end
+
+  def down
+    # Not needed
+  end
+end

db/schema_migrations/20201228110136

+6488e3542276042f302d79533e3e84c43a4ef471535137bcef11e73a0e4d961f
\ No newline at end of file

db/schema_migrations/20201228110238

+7be98c4f62df9fd837f7a547916dd5481c0b4da2d4fc6680b104b2a998be1eed
\ No newline at end of file

db/schema_migrations/20201231133921

+26bf4abb73a53f71fbcb8b5cd1ae1e1539ec59e7052b3bbed95ab1de3fda3de7
\ No newline at end of file

db/structure.sql

@@ -13544,6 +13544,30 @@ CREATE TABLE issues_self_managed_prometheus_alert_events (
     updated_at timestamp with time zone NOT NULL
 );
 
+CREATE TABLE iteration_cadences (
+    id bigint NOT NULL,
+    group_id bigint NOT NULL,
+    created_at timestamp with time zone NOT NULL,
+    updated_at timestamp with time zone NOT NULL,
+    start_date date NOT NULL,
+    last_run_date date,
+    duration_in_weeks integer,
+    iterations_in_advance integer,
+    active boolean DEFAULT true NOT NULL,
+    automatic boolean DEFAULT true NOT NULL,
+    title text NOT NULL,
+    CONSTRAINT check_6b6fe7cdea CHECK ((char_length(title) <= 255))
+);
+
+CREATE SEQUENCE iteration_cadences_id_seq
+    START WITH 1
+    INCREMENT BY 1
+    NO MINVALUE
+    NO MAXVALUE
+    CACHE 1;
+
+ALTER SEQUENCE iteration_cadences_id_seq OWNED BY iteration_cadences.id;
+
 CREATE TABLE jira_connect_installations (
     id bigint NOT NULL,
     client_key character varying,
@@ -17356,6 +17380,7 @@ CREATE TABLE sprints (
     description text,
     description_html text,
     state_enum smallint DEFAULT 1 NOT NULL,
+    iteration_cadence_id integer,
     CONSTRAINT sprints_must_belong_to_project_or_group CHECK ((((project_id <> NULL::bigint) AND (group_id IS NULL)) OR ((group_id <> NULL::bigint) AND (project_id IS NULL)))),
     CONSTRAINT sprints_title CHECK ((char_length(title) <= 255))
 );
@@ -19067,6 +19092,8 @@ ALTER TABLE ONLY issue_user_mentions ALTER COLUMN id SET DEFAULT nextval('issue_
 
 ALTER TABLE ONLY issues ALTER COLUMN id SET DEFAULT nextval('issues_id_seq'::regclass);
 
+ALTER TABLE ONLY iteration_cadences ALTER COLUMN id SET DEFAULT nextval('iteration_cadences_id_seq'::regclass);
+
 ALTER TABLE ONLY jira_connect_installations ALTER COLUMN id SET DEFAULT nextval('jira_connect_installations_id_seq'::regclass);
 
 ALTER TABLE ONLY jira_connect_subscriptions ALTER COLUMN id SET DEFAULT nextval('jira_connect_subscriptions_id_seq'::regclass);
@@ -20361,6 +20388,9 @@ ALTER TABLE ONLY issues_prometheus_alert_events
 ALTER TABLE ONLY issues_self_managed_prometheus_alert_events
     ADD CONSTRAINT issues_self_managed_prometheus_alert_events_pkey PRIMARY KEY (issue_id, self_managed_prometheus_alert_event_id);
 
+ALTER TABLE ONLY iteration_cadences
+    ADD CONSTRAINT iteration_cadences_pkey PRIMARY KEY (id);
+
 ALTER TABLE ONLY sprints
     ADD CONSTRAINT iteration_start_and_due_daterange_group_id_constraint EXCLUDE USING gist (group_id WITH =, daterange(start_date, due_date, '[]'::text) WITH &&) WHERE ((group_id IS NOT NULL));
 
@@ -22440,6 +22470,8 @@ CREATE INDEX index_issues_on_updated_at ON issues USING btree (updated_at);
 
 CREATE INDEX index_issues_on_updated_by_id ON issues USING btree (updated_by_id) WHERE (updated_by_id IS NOT NULL);
 
+CREATE INDEX index_iteration_cadences_on_group_id ON iteration_cadences USING btree (group_id);
+
 CREATE UNIQUE INDEX index_jira_connect_installations_on_client_key ON jira_connect_installations USING btree (client_key);
 
 CREATE INDEX index_jira_connect_subscriptions_on_namespace_id ON jira_connect_subscriptions USING btree (namespace_id);
@@ -23428,6 +23460,8 @@ CREATE UNIQUE INDEX index_sop_configs_on_project_id ON security_orchestration_po
 
 CREATE UNIQUE INDEX index_sop_configs_on_security_policy_management_project_id ON security_orchestration_policy_configurations USING btree (security_policy_management_project_id);
 
+CREATE INDEX index_sprints_iteration_cadence_id ON sprints USING btree (iteration_cadence_id);
+
 CREATE INDEX index_sprints_on_description_trigram ON sprints USING gin (description gin_trgm_ops);
 
 CREATE INDEX index_sprints_on_due_date ON sprints USING btree (due_date);
@@ -24694,6 +24728,9 @@ ALTER TABLE ONLY project_group_links
 ALTER TABLE ONLY epics
     ADD CONSTRAINT fk_dccd3f98fc FOREIGN KEY (assignee_id) REFERENCES users(id) ON DELETE SET NULL;
 
+ALTER TABLE ONLY sprints
+    ADD CONSTRAINT fk_de14ba038f FOREIGN KEY (iteration_cadence_id) REFERENCES iteration_cadences(id) ON DELETE CASCADE;
+
 ALTER TABLE ONLY analytics_devops_adoption_segment_selections
     ADD CONSTRAINT fk_ded7fe0344 FOREIGN KEY (group_id) REFERENCES namespaces(id) ON DELETE CASCADE;
 
@@ -25087,6 +25124,9 @@ ALTER TABLE ONLY packages_debian_group_component_files
 ALTER TABLE ONLY boards_epic_board_labels
     ADD CONSTRAINT fk_rails_2bedeb8799 FOREIGN KEY (label_id) REFERENCES labels(id) ON DELETE CASCADE;
 
+ALTER TABLE ONLY iteration_cadences
+    ADD CONSTRAINT fk_rails_2cbf3ce526 FOREIGN KEY (group_id) REFERENCES namespaces(id) ON DELETE CASCADE;
+
 ALTER TABLE ONLY onboarding_progresses
     ADD CONSTRAINT fk_rails_2ccfd420cc FOREIGN KEY (namespace_id) REFERENCES namespaces(id) ON DELETE CASCADE;