better error handling and reporting for heroku deploy task

Rakefile

@@ -21,18 +21,39 @@ end
 desc <<-DESC
 Deploy application to heroku.
   account=[name] if multiple heroku accounts
+  app=[name]     if a different app name than directory
 DESC
 task :deploy do
   system "git init 1>/dev/null"
   remotes = `git remote`.chomp.split("\n")
   if remotes.include? 'heroku'
     `git push heroku master`
   else
-    app_name = File.basename(File.expand_path("..", __FILE__))
+    command = ['heroku', 'apps:create']
+    app_name = ENV['app'].dup if ENV['app']
+    app_name ||= File.basename(File.expand_path("..", __FILE__))
     app_name.gsub!('_', '-')
-    options = "-s cedar"
-    options << " --account=#{ENV['account']}" if ENV['account']
-    `heroku apps:create #{app_name} #{options}`
+    command << app_name
+    command << ['-s', 'cedar']
+    command << ['--account', ENV['account']] if ENV['account']
+    command.flatten!
+    puts "Executing: #{command * ' '}\n\n"
+    output = IO.popen(command << {:err => [:child, :out]}) do |io|
+      io.read
+    end
+    unless $?.success?
+      puts "Something went wrong.\n"
+      case output
+      when /No account specified/
+        puts "Ambiguous heroku accounts, try 'rake deploy account=youraccount'"
+      when /Name is already taken/
+        puts "App name already taken, try 'rake deploy app=another-app-name'"
+      else
+        puts output
+      end
+    else
+      puts output
+    end
   end
 end