Set particular locales for application (#135)

[seniorihor]

No description provided.

[coveralls]

Coverage increased (+0.2%) to 99.76% when pulling e915793 on defself:master into c24a2ed on kslazarev:master.

[coveralls]

Coverage decreased (-0.1%) to 99.403% when pulling e915793 on defself:master into c24a2ed on kslazarev:master.

[coveralls]

Coverage decreased (-0.1%) to 99.403% when pulling d5146ac on defself:master into c24a2ed on kslazarev:master.

[coveralls]

Coverage decreased (-0.1%) to 99.403% when pulling 2bfec0d on defself:master into c24a2ed on kslazarev:master.

[dblock]

This works but I don't love it as it sets a global constant for configuration. There be dragons. At the very least it feels like it requires complicated gymnastics like require: false and manual loading. There's probably a simpler solution to delay setting I18n.locale_file setting and/or to unload whatever is there when the locales are assigned and replace with new values.

I think as a developer I'd want to do this, which is similar to other gems:

NumbersAndWords.configure do |config|
   config.locales = [:en, :ru]
end

[coveralls]

Coverage decreased (-32.9%) to 66.624% when pulling 399d9cf on defself:master into c24a2ed on kslazarev:master.

[coveralls]

Coverage decreased (-0.1%) to 99.403% when pulling 4168153 on defself:master into c24a2ed on kslazarev:master.