feat: Add bulk imports API for contacts (#1724)

db/migrate/20210201150037_create_data_imports.rb

@@ -0,0 +1,14 @@
+class CreateDataImports < ActiveRecord::Migration[6.0]
+  def change
+    create_table :data_imports do |t|
+      t.references :account, null: false, foreign_key: true
+      t.string :data_type, null: false
+      t.integer :status, null: false, default: 0
+      t.text :processing_errors
+      t.integer :total_records
+      t.integer :processed_records
+
+      t.timestamps
+    end
+  end
+end