changed rails dependency "~>4.2" to ">= 4.2"

[brijeshror]

1. Updated rails dependencies to ">= 4.2"
2. Used simplecov in rspec instead of codeclimate-test-reporter, because Usage of Code Climate Test Reporter is deprecated in version +1.0

W, [2017-06-23T14:10:21.546973 #31050] WARN -- : This usage of the Code Climate Test Reporter is now deprecated. Since version
1.0, we now require you to run SimpleCov in your test/spec helper, and then
run the provided codeclimate-test-reporter binary separately to report your
results to Code Climate.
More information here: https://github.com/codeclimate/ruby-test-reporter/blob/master/README.md

Look https://docs.codeclimate.com/v1.0/docs/test-coverage-ruby to use codeclimate now.

3. Removed Active Record call back config config.active_record.raise_in_transactional_callbacks. No longer required.
   Reference : http://edgeguides.rubyonrails.org/upgrading_ruby_on_rails.html#error-handling-in-transaction-callbacks

4. Added railtie to set active_record configbelongs_to_required_by_default to false, Because to resolve validation errors,

   • Validation failed: Post must exist
   • Validation failed: Parent must exist

Error rises when trying to create record without defining association belongs_to field value in which default value specified at DB level.
Either we can use optional or required options in belongs_to association. Or we can add active_record config belongs_to_required_by_default to resolve this issue.
References :
http://blog.bigbinary.com/2016/02/15/rails-5-makes-belong-to-association-required-by-default.html
https://stackoverflow.com/questions/38983666/validation-failed-class-must-exist/38986580#38986580
http://edgeguides.rubyonrails.org/5_0_release_notes.html#active-record-notable-changes

[flackou]

Hi @brijeshror,

First of all, thanks for this PR. Unfortunately it doesn't seem to be compatible with Rails 5.2 : if you try to launch the gem tests after upgrading Rails, you'll get this error :

% bundle exec rake
...
55 examples, 0 failures, 1 pending
% bundle update rails
...
Using rails 5.2.0 (was 4.2.9)
Using rails_wordpress 0.2.1 from source at `.`
Bundle updated!
% bundle exec rake   
rake aborted!
NoMethodError: undefined method `sqlite3=' for #<Class:0x007fbd0864a650>
/Users/jlestavel/Work/github/rails_wordpress/lib/rails_wordpress/railtie.rb:9:in `block (3 levels) in <class:Railtie>'
/Users/jlestavel/Work/github/rails_wordpress/lib/rails_wordpress/railtie.rb:9:in `each'
/Users/jlestavel/Work/github/rails_wordpress/lib/rails_wordpress/railtie.rb:9:in `block (2 levels) in <class:Railtie>'

It seems related to https://github.com/rails/rails/pull/29699/files.

I started to look at what I can do to fix that but in fact I'm a bit embarrassed that the gem now forces belongs_to_required_by_default to false. For example, I use this gem as an engine in a larger Rails app, with another database aside, and I don't want my app setting to be globally changed by a gem ! So I can work on a fix but I would like your opinion before : is it OK if I remove the Railties and add optional: true to all the belongs_to ? Or is there something else I don't see ?

Thanks for your help 😃 ,

Julien

PS : @mwlang of course your opinion is welcome too !