Feature: Report improvements (#6967) (#7000)

* Implement Assignment of Reports (#6967)

* Change translation of admin.report.comment.label to "Report Comment" for clarity

As we'll soon add the ability for reports to have comments on them, this clarification makes sense.

* Implement notes for Reports

This enables moderators to leave comments about a report whilst they work on it

* Fix display of report moderation notes

* Allow reports to be reopened / marked as unresolved

* Redirect to reports listing upon resolution of report

* Implement "resolve with note" functionality

* Add inverse relationship for report notes

* Remove additional database querying when loading report notes

* Fix tests for reports

* Fix localisations for report notes / reports

db/migrate/20180402031200_add_assigned_account_id_to_reports.rb

@@ -0,0 +1,5 @@
+class AddAssignedAccountIdToReports < ActiveRecord::Migration[5.1]
+  def change
+    add_reference :reports, :assigned_account, null: true, default: nil, foreign_key: { on_delete: :nullify, to_table: :accounts }, index: false
+  end
+end

db/migrate/20180402040909_create_report_notes.rb

@@ -0,0 +1,14 @@
+class CreateReportNotes < ActiveRecord::Migration[5.1]
+  def change
+    create_table :report_notes do |t|
+      t.text :content, null: false
+      t.references :report, null: false
+      t.references :account, null: false
+
+      t.timestamps
+    end
+
+    add_foreign_key :report_notes, :reports, column: :report_id, on_delete: :cascade
+    add_foreign_key :report_notes, :accounts, column: :account_id, on_delete: :cascade
+  end
+end