rakefile + update gemspec

Rakefile

@@ -0,0 +1,19 @@
+require 'rake'
+
+begin
+  require 'jeweler'
+  Jeweler::Tasks.new do |gemspec|
+    gemspec.name = "decisiontree"
+    gemspec.summary = "ID3-based implementation of the M.L. Decision Tree algorithm"
+    gemspec.description = gemspec.summary
+    gemspec.email = "ilya@igvita.com"
+    gemspec.homepage = "http://github.com/igrigorik/decisiontree"
+    gemspec.authors = ["Ilya Grigorik"]
+    gemspec.rubyforge_project = "decisiontree"
+  end
+
+  Jeweler::GemcutterTasks.new
+rescue LoadError
+  puts "Jeweler not available. Install it with: sudo gem install technicalpickles-jeweler -s http://gems.github.com"
+end
+