chore: process self hosted migrations

app/services/import/external_model.rb

@@ -0,0 +1,2 @@
+class Import::ExternalModel < ApplicationRecord
+end

app/services/import/process_from_self_hosted_service.rb

@@ -0,0 +1,59 @@
+class Import::ProcessFromSelfHostedService
+  MODELS_TO_IMPORT = [CannedResponse, Label, Team, CustomAttributeDefinition].freeze
+  ATTRIBUTES_TO_IMPORT = {
+    'canned_responses' => %w[title content short_code],
+    'labels' => %w[color description show_in_sidebar title],
+    'teams' => %w[name description allow_auto_assign],
+    'custom_attribute_definitions' => %w[attribute_description attribute_display_name attribute_display_type attribute_key attribute_model
+                                         attribute_values default_value]
+  }.freeze
+
+  def initialize(account_object, external_account_id, database_config)
+    @account_object = account_object
+    @external_account_id = external_account_id
+    @database_config = database_config.merge({
+                                               adapter: 'postgresql',
+                                               encoding: 'unicode'
+                                             })
+  end
+
+  def perform
+    MODELS_TO_IMPORT.each do |model|
+      # Create a dynamic subclass of the model with the external connection established
+      external_model = get_external_model(model)
+
+      # Fetch the data from the external account
+      external_account_data = fetch_external_account_data(external_model)
+
+      # Import the data to the local account
+      import_data_to_local_account(external_account_data, model)
+    end
+  end
+
+  private
+
+  def get_external_model(model)
+    klass = Import::ExternalModel
+    klass.table_name = model.table_name
+    klass.establish_connection(@database_config)
+    klass
+  end
+
+  def fetch_external_account_data(external_model)
+    external_model.where(account_id: @external_account_id)
+  end
+
+  def import_data_to_local_account(external_account_data, model)
+    # Update the account_id and save the records to the local database
+
+    records_to_import = []
+    external_account_data.each do |record|
+      new_record = model.new
+      new_record.assign_attributes(record.attributes.slice(*ATTRIBUTES_TO_IMPORT[model.table_name]))
+      new_record.account_id = @account_object.id
+      records_to_import << new_record
+    end
+
+    model.import records_to_import, on_duplicate_key_ignore: true
+  end
+end