Merge branch 'use-activerecord_sane_schema_dumper' into 'master'

Use activerecord_sane_schema_dumper

## What does this MR do?

> `ActiveRecord::SaneSchemaDumper` modifies the behavior of Rails’ `ActiveRecord::SchemaDumper` so that the generated `db/schema.rb` file doesn’t contain any useless/harmful whitespace column alignment.

## Why was this MR needed?

To reduce potential conflicts in `db/schema.rb` (see https://gitlab.com/gitlab-org/gitlab-ee/issues/715).

See merge request !6827

Gemfile

@@ -262,6 +262,8 @@ group :development do
 
   # thin instead webrick
   gem 'thin', '~> 1.7.0'
+
+  gem 'activerecord_sane_schema_dumper', '0.2'
 end
 
 group :development, :test do

Gemfile.lock

@@ -38,6 +38,8 @@ GEM
       multi_json (~> 1.11, >= 1.11.2)
       rack (>= 1.5.2, < 3)
       railties (>= 4.0, < 5.1)
+    activerecord_sane_schema_dumper (0.2)
+      rails (>= 4, < 5)
     activesupport (4.2.7.1)
       i18n (~> 0.7)
       json (~> 1.7, >= 1.7.7)
@@ -805,6 +807,7 @@ DEPENDENCIES
   RedCloth (~> 4.3.2)
   ace-rails-ap (~> 4.1.0)
   activerecord-session_store (~> 1.0.0)
+  activerecord_sane_schema_dumper (= 0.2)
   acts-as-taggable-on (~> 4.0)
   addressable (~> 2.3.8)
   after_commit_queue (~> 1.3.0)