Allow the ruby-debug related gems to be conditionally excluded for IDE development.

Fixes #CNVS-3710

Testing Notes:
===========
* Using an editor like RubyMine, add an environment setting for development
   called DISABLE_RUBY_DEBUGGING with a value of something like "1". Specific
   value is unimportant.
* Start a 'debug' session and set breakpoints and verify they fire.
* Using console based debugging, verify that the execution pauses
   when a DEBUG statement is reached.

Change-Id: Iec59efeb291827ee600b7184bce3990145189b47
Reviewed-on: https://gerrit.instructure.com/17540
Tested-by: Jenkins <jenkins@instructure.com>
Reviewed-by: Jon Willesen <jonw@instructure.com>
QA-Review: Marc LeGendre <marc@instructure.com>

Gemfile

@@ -109,10 +109,15 @@ group :development do
   gem 'rb-fsevent', :require => false
   gem 'rb-fchange', :require => false
 
-  if ONE_NINE
-    gem 'debugger',     '1.1.3'
-  else
-    gem 'ruby-debug',   '0.10.4'
+  # Option to DISABLE_RUBY_DEBUGGING is helpful IDE-based debugging.
+  # The ruby debug gems conflict with the IDE-based debugger gem.
+  # Set this option in your dev environment to disable.
+  unless ENV['DISABLE_RUBY_DEBUGGING']
+    if ONE_NINE
+      gem 'debugger',     '1.1.3'
+    else
+      gem 'ruby-debug',   '0.10.4'
+    end
   end
 end
 

config/environments/development.rb

@@ -40,8 +40,14 @@ Dir[File.dirname(__FILE__) + "/" + File.basename(__FILE__, ".rb") + "-*.rb"].eac
 
 # allow debugging only in development environment by default
 # ruby-debug is currently broken in 1.9.3
-if RUBY_VERSION < "1.9."
-  require "ruby-debug"
-else
-  require "debugger"
-end
+#
+# Option to DISABLE_RUBY_DEBUGGING is helpful IDE-based debugging.
+# The ruby debug gems conflict with the IDE-based debugger gem.
+# Set this option in your dev environment to disable.
+unless ENV['DISABLE_RUBY_DEBUGGING']
+  if RUBY_VERSION < "1.9."
+    require "ruby-debug"
+  else
+    require "debugger"
+  end
+end