Create a join model for request issues and decision issues (#7886)

This is the first PR for #7884

### Description
1. Create a join model RequestDecisionIssue and the associated table.
2. Start writing to the new table for HLR and SC as well as to the source_request_issue_id column

app/models/decision_issue.rb

@@ -1,4 +1,5 @@
 class DecisionIssue < ApplicationRecord
   validates :disposition, inclusion: { in: Constants::ISSUE_DISPOSITIONS_BY_ID.keys.map(&:to_s) }, allow_nil: true
+  # TODO: has_many :request_issues, through: :request_decision_issues
   belongs_to :source_request_issue, class_name: "RequestIssue"
 end

app/models/rating_issue.rb

@@ -47,14 +47,22 @@ def save_decision_issue
     # if a DecisionIssue already exists then do not touch it. These should be immutable.
     return if decision_issue
 
-    DecisionIssue.create!(
-      source_request_issue: source_request_issue,
-      rating_issue_reference_id: reference_id,
-      participant_id: participant_id,
-      promulgation_date: promulgation_date,
-      decision_text: decision_text,
-      profile_date: profile_date
-    )
+    ActiveRecord::Base.transaction do
+      created_decision_issue = DecisionIssue.create!(
+        source_request_issue: source_request_issue,
+        rating_issue_reference_id: reference_id,
+        participant_id: participant_id,
+        promulgation_date: promulgation_date,
+        decision_text: decision_text,
+        profile_date: profile_date
+      )
+
+      RequestDecisionIssue.create!(
+        request_issue: source_request_issue,
+        decision_issue: created_decision_issue
+      )
+      created_decision_issue
+    end
   end
 
   # If you change this method, you will need to clear cache in prod for your changes to

app/models/request_decision_issue.rb

@@ -0,0 +1,4 @@
+class RequestDecisionIssue < ApplicationRecord
+  belongs_to :request_issue
+  belongs_to :decision_issue
+end

app/models/request_issue.rb

@@ -3,6 +3,7 @@ class RequestIssue < ApplicationRecord
 
   belongs_to :review_request, polymorphic: true
   belongs_to :end_product_establishment
+  # TODO: has_many :decision_issues, through: :request_decision_issues
   has_many :decision_issues, foreign_key: "source_request_issue_id"
   has_many :remand_reasons
   has_many :duplicate_but_ineligible, class_name: "RequestIssue", foreign_key: "ineligible_due_to_id"

db/migrate/20181116155733_create_request_decision_issues.rb

@@ -0,0 +1,9 @@
+class CreateRequestDecisionIssues < ActiveRecord::Migration[5.1]
+  def change
+    create_table :request_decision_issues do |t|
+      t.integer :request_issue_id
+      t.integer :decision_issue_id
+      t.timestamps
+    end
+  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.define(version: 20181114142531) do
+ActiveRecord::Schema.define(version: 20181116155733) do
 
   # These are extensions that must be enabled in order to support this database
   enable_extension "plpgsql"
@@ -635,6 +635,13 @@
     t.index ["request_issue_id"], name: "index_remand_reasons_on_request_issue_id"
   end
 
+  create_table "request_decision_issues", force: :cascade do |t|
+    t.integer "request_issue_id"
+    t.integer "decision_issue_id"
+    t.datetime "created_at", null: false
+    t.datetime "updated_at", null: false
+  end
+
   create_table "request_issues", force: :cascade do |t|
     t.string "review_request_type"
     t.bigint "review_request_id"
@@ -654,12 +661,12 @@
     t.bigint "ineligible_due_to_id"
     t.boolean "untimely_exemption"
     t.text "untimely_exemption_notes"
+    t.string "ineligible_reason"
     t.string "ramp_claim_id"
     t.datetime "decision_sync_submitted_at"
     t.datetime "decision_sync_attempted_at"
     t.datetime "decision_sync_processed_at"
     t.string "decision_sync_error"
-    t.string "ineligible_reason"
     t.index ["contention_reference_id", "removed_at"], name: "index_request_issues_on_contention_reference_id_and_removed_at", unique: true
     t.index ["end_product_establishment_id"], name: "index_request_issues_on_end_product_establishment_id"
     t.index ["ineligible_due_to_id"], name: "index_request_issues_on_ineligible_due_to_id"

spec/models/rating_issue_spec.rb

@@ -214,6 +214,7 @@
       expect(subject.decision_issue).to be_a(DecisionIssue)
       expect(subject.decision_issue.rating_issue_reference_id).to eq(reference_id)
       expect(subject.decision_issue.source_request_issue).to eq(request_issue)
+      expect(RequestDecisionIssue.where(decision_issue: subject.decision_issue).first).to_not be_nil
     end
 
     it "does not save duplicates" do