Ruby 2.6.5. support

[jerko-culina]

On ruby 2.6.5 I got next error

Productive::TimeReport.where(person_id: ids).all
NoMethodError: undefined method `merge' for nil:NilClass
from /Users/hajvan/.rbenv/versions/2.6.5/lib/ruby/gems/2.6.0/gems/json_api_client-1.5.2/lib/json_api_client/resource.rb:295:in _build_connection'

[jerko-culina]

I figured it out.
This is how it looks the config/initialize/productive.rb file in my case.

if ENV['PRODUCTIVE_API_KEY'] && ENV['PRODUCTIVE_ACCOUNT_ID']
  Productive.configure do |config|
    config.api_key = ENV.fetch('PRODUCTIVE_API_KEY')
    config.account_id = ENV.fetch('PRODUCTIVE_ACCOUNT_ID')
  end
end

Because I did not have ENV keys and Productive.configure was never run. After adding ENV variables it works perfectly!