Renamed from_username to outgoing_name

* hopefully this makes field name little bit clearer

changelogs/unreleased/service-desk-name.yml

+---
+title: Added migration which adds service desk username column
+merge_request: 21733
+author:
+type: added

db/migrate/20191213104838_add_service_desk_username.rb

+# frozen_string_literal: true
+
+class AddServiceDeskUsername < ActiveRecord::Migration[5.2]
+  DOWNTIME = false
+
+  def change
+    add_column :service_desk_settings, :outgoing_name, :string, limit: 255
+  end
+end

db/schema.rb

@@ -3663,6 +3663,7 @@ ActiveRecord::Schema.define(version: 2019_12_17_160632) do
 
   create_table "service_desk_settings", primary_key: "project_id", id: :bigint, default: nil, force: :cascade do |t|
     t.string "issue_template_key", limit: 255
+    t.string "outgoing_name", limit: 255
   end
 
   create_table "services", id: :serial, force: :cascade do |t|

ee/app/models/service_desk_setting.rb

@@ -6,6 +6,7 @@ class ServiceDeskSetting < ApplicationRecord
   belongs_to :project
   validates :project_id, presence: true
   validate :valid_issue_template
+  validates :outgoing_name, length: { maximum: 255 }, allow_blank: true
 
   def self.update_template_key_for(project:, issue_template_key:)
     return unless issue_template_key

ee/spec/models/service_desk_setting_spec.rb

@@ -5,6 +5,7 @@ require 'spec_helper'
 describe ServiceDeskSetting do
   describe 'validations' do
     it { is_expected.to validate_presence_of(:project_id) }
+    it { is_expected.to validate_length_of(:outgoing_name).is_at_most(255) }
   end
 
   describe 'associations' do

lib/gitlab/import_export/import_export.yml

@@ -220,6 +220,8 @@ excluded_attributes:
     - :encrypted_token
     - :encrypted_token_iv
     - :enabled
+  service_desk_setting:
+    - :outgoing_name
 
 methods:
   notes: