Add DossierOperationLog model

db/migrate/20181123195208_create_dossier_operation_logs.rb

@@ -0,0 +1,11 @@
+class CreateDossierOperationLogs < ActiveRecord::Migration[5.2]
+  def change
+    create_table :dossier_operation_logs do |t|
+      t.string :operation, null: false
+      t.references :dossier, foreign_key: true, index: true
+      t.references :gestionnaire, foreign_key: true, index: true
+
+      t.timestamps
+    end
+  end
+end