Updated grape-roar to 0.4.0

Fixes compatibility problems with representable 2.4+. An API change
meant that the current way of passing in the rack environment was
getting clobbered, and we were unable to access the context of the
request.

See
https://github.com/ruby-grape/grape-roar/pull/21/files
for the fix

and conversation in
slack-ruby#43

Change properties to `public` methods

See slack-ruby#45 - slack-ruby#45

trailblazer/representable@74155a9
changed to use `public_send` for these types of methods.

Use danger format

CHANGELOG.md

@@ -2,6 +2,7 @@
 
 #### 0.5.1 (Next)
 
+* [#45](https://github.com/slack-ruby/slack-ruby-bot-server/pull/45): Update dependencies so we can follow the latest `representable`. - [@swalberg](https://github.com/swalberg).
 * Your contribution here.
 
 #### 0.5.0 (2/9/2017)

lib/slack-ruby-bot-server/api/presenters/status_presenter.rb

@@ -14,8 +14,6 @@ module StatusPresenter
         property :active_teams_count
         property :ping
 
-        private
-
         def ping
           team = Team.asc(:_id).first
           return unless team

slack-ruby-bot-server.gemspec

@@ -21,8 +21,7 @@ Gem::Specification.new do |spec|
   spec.add_dependency 'unicorn'
   spec.add_dependency 'grape'
   spec.add_dependency 'grape-swagger'
-  spec.add_dependency 'roar', '~> 1.0.4'
-  spec.add_dependency 'grape-roar'
+  spec.add_dependency 'grape-roar', '~> 0.4.0'
   spec.add_dependency 'rack-cors'
   spec.add_dependency 'kaminari-mongoid'
   spec.add_dependency 'kaminari-grape'