dev: add support for a Gemfile-custom file so devs can customize their

dev env.

.gitignore

@@ -14,3 +14,5 @@ Gemfile.lock
 bin
 .rbx
 .yardoc
+vendor
+Gemfile-custom

Gemfile

@@ -47,22 +47,10 @@ group :development do
   end
 
   platforms :mri_19 do
-    gem 'ruby-debug19', '~> 0.11.6'
-    if RUBY_VERSION == '1.9.3' && !ENV['TRAVIS']
-      if `gem list ruby-debug-base19` =~ /0\.11\.26/
-        gem 'ruby-debug-base19', '0.11.26'
-      else
-        warn "Download and install ruby-debug-base19-0.11.26 from http://rubyforge.org/frs/shownotes.php?release_id=46303"
-      end
-
-      if `gem list linecache19` =~ /0\.5\.13/
-        gem 'linecache19', '0.5.13'
-      else
-        warn "Download and install linecache19-0.5.13 from http://rubyforge.org/frs/download.php/75414/linecache19-0.5.13.gem"
-      end
-    else
-      gem 'ruby-debug-base19', '~> 0.11.25'
-      gem 'linecache19',       '~> 0.5.12'
+    if RUBY_VERSION == '1.9.2'
+      gem 'ruby-debug19',      '0.11.6'
+      gem 'ruby-debug-base19', '0.11.25'
+      gem 'linecache19',       '0.5.12'
     end
   end
 
@@ -71,3 +59,5 @@ group :development do
     gem "ruby-prof", "~> 0.10.0"
   end
 end
+
+eval File.read('Gemfile-custom') if File.exist?('Gemfile-custom')