add model and javascript validations for accounts

fixes CNVS-3047

testing steps:
- create a new account
- edit the account and remove the "Account Name"
  try to save and verify an error displays
- edit the account name and make it longer than 255
  and verify it displays it is too long

Change-Id: I9437a16ea5f897a7ee214dcdb3b453599f99c1f7
Reviewed-on: https://gerrit.instructure.com/23465
Tested-by: Jenkins <jenkins@instructure.com>
Reviewed-by: Jon Jensen <jon@instructure.com>
Reviewed-by: Landon Wilkins <lwilkins@instructure.com>
Product-Review: Marc LeGendre <marc@instructure.com>
QA-Review: Marc LeGendre <marc@instructure.com>

app/models/account.rb

@@ -96,6 +96,7 @@ class Account < ActiveRecord::Base
   time_zone_attribute :default_time_zone, default: "America/Denver"
 
   validates_locale :default_locale, :allow_nil => true
+  validates_length_of :name, :maximum => maximum_string_length, :allow_blank => true
   validate :account_chain_loop, :if => :parent_account_id_changed?
   validate :validate_auth_discovery_url
 

public/javascripts/account_settings.js

@@ -17,6 +17,7 @@ define([
 
   $(document).ready(function() {
     $("#account_settings").submit(function() {
+      var $this = $(this);
       $(".ip_filter .value").each(function() {
         $(this).removeAttr('name');
       }).filter(":not(.blank)").each(function() {
@@ -25,6 +26,19 @@ define([
           $(this).attr('name', 'account[ip_filters][' + name + ']');
         }
       });
+      var validations = {
+        object_name: 'account',
+        required: ['name'],
+        property_validations: {
+          'name': function(value){
+            if (value && value.length > 255) { return I18n.t("account_name_too_long", "Account Name is too long")}
+          }
+        }
+      };
+      var result = $this.validateForm(validations);
+      if(!result) {
+        return false;
+      }
     });
     $(".datetime_field").datetime_field();
     $("#add_notification_form textarea").editorBox().width('100%');