patch jruby utf-8 method naming, fixes #1507
Use `JRUBY_VERSION` instead of `RUBY_VERSION`.
Merge pull request #1508 from padrino/1507-fix-jruby-utf

patch jruby utf-8 method naming, fixes #1507
Remove charset from json mimetype, fixes compatibility with sinatra edge.

Set :add_charset option for old sinatra version.

Replace `unless~else` with `if~else`, remove an array.
Merge pull request #1505 from padrino/remove-charset-from-json

Remove charset from json mimetype, fixes compatibility with sinatra edge.
Fixes deprecated AR::Migrator constructor used in ar:abort_if_pending_migrations

As of this Rails commit [0], it is no longer legal to pass a string
constructor instead of a list of migration paths. This commit deletes
the deprecated approach and uses the recommended approach, passing the
list of paths to migrate.

[0] https://github.com/rails/rails/commit/685631285f21e2f63b1ecbdb1495f25c97b6bf41
Merge pull request #1510 from fj/topic/remove-ar-deprecations

Fixes deprecated AR::Migrator constructor used in ar:abort_if_pending_migrations
fix so rake spec runs once with empty folder
Fix Typo
Extract some behaviors to methods
Fix Typo on Comment
Merge pull request #1513 from scudelletti/ds-padrino

Extracting logic to methods to improve readability
I18n.enforce_available_locales should be true.

This gets rid of some deprecation warnings on tests
and in apps using I18n.

ref:
https://github.com/svenfuchs/i18n/commit/3b6e56e06fd70f6e4507996b017238505e66608c

ref:
http://stackoverflow.com/questions/20361428/rails-i18n-validation-deprecation-warning
correctly set a name of mounted application, fixes #1517
Merge pull request #1506 from mitchellhenke/fix-rspec-multiple-runs

Empty folder in spec folder causes rspec's rake task to run tests multiple times
Add :flush option to content_for.
Merge pull request #1518 from padrino/add-flush-to-content_for

Add :flush option to content_for.
Merge pull request #1514 from Ortuna/I18n-locale-check

I18n.enforce_available_locales should be true.
Add Rakefile tasks to the component generator
Merge pull request #1523 from tyabe/fix_component_generator

Add Rakefile tasks to the component generator