move and slightly refactor benchmark rake task

Rakefile

@@ -36,18 +36,5 @@ end
 
 task :default => :spec
 
-def define_bench_task(feature)
-  desc "Run #{feature} benchmarks"
-  task(feature){ ruby "benchmark/#{feature}.rb" }
-end
-
-namespace :bench do
-  define_bench_task :active_record
-  define_bench_task :escape
-  define_bench_task :query_with_mysql_casting
-  define_bench_task :query_without_mysql_casting
-  define_bench_task :sequel
-  define_bench_task :allocations
-  define_bench_task :thread_alone
-end# Load custom tasks
+# Load custom tasks
 Dir['tasks/*.rake'].sort.each { |f| load f }

tasks/benchmarks.rake

@@ -0,0 +1,8 @@
+namespace :bench do
+  [ :active_record, :escape, :query_with_mysql_casting,
+    :query_without_mysql_casting, :sequel, :allocations,
+    :thread_alone].each do |feature|
+      desc "Run #{feature} benchmarks"
+      task(feature){ ruby "benchmark/#{feature}.rb" }
+  end
+end