Ditch `Commands` namespace for base command.

Reading `Rails::Commands::Command` feels excessive. Especially if users can subclass command
to write their own commands — which I'd like to aim for.

Switch to `Rails::Command` before we get too far into things.

railties/lib/rails/command.rb

+require 'rails/commands/commands_tasks'
+
+module Rails
+  class Command
+    attr_reader :argv
+
+    def initialize(argv = [])
+      @argv = argv
+
+      @option_parser = build_option_parser
+      @options = {}
+    end
+
+    def self.run(task_name, argv)
+      command_name = command_name_for(task_name)
+
+      if command = command_for(command_name)
+        command.new(argv).run(command_name)
+      else
+        Rails::CommandsTasks.new(argv).run_command!(task_name)
+      end
+    end
+
+    def run(command_name)
+      parse_options_for(command_name)
+      @option_parser.parse! @argv
+
+      public_send(command_name)
+    end
+
+    def self.options_for(command_name, &options_to_parse)
+      @@command_options[command_name] = options_to_parse
+    end
+
+    def self.set_banner(command_name, banner)
+      options_for(command_name) { |opts, _| opts.banner = banner }
+    end
+
+    private
+      @@commands = []
+      @@command_options = {}
+
+      def parse_options_for(command_name)
+        @@command_options.fetch(command_name, proc {}).call(@option_parser, @options)
+      end
+
+      def build_option_parser
+        OptionParser.new do |opts|
+          opts.on('-h', '--help', 'Show this help.') do
+            puts opts
+            exit
+          end
+        end
+      end
+
+      def self.inherited(command)
+        @@commands << command
+      end
+
+      def self.command_name_for(task_name)
+        task_name.gsub(':', '_').to_sym
+      end
+
+      def self.command_for(command_name)
+        @@commands.find do |command|
+          command.public_instance_methods.include?(command_name)
+        end
+      end
+  end
+end

railties/lib/rails/commands.rb

+ARGV << '--help' if ARGV.empty?
+
 aliases = {
   "g"  => "generate",
   "d"  => "destroy",
@@ -8,15 +10,10 @@
   "t"  => "test",
 }
 
-if ARGV.empty?
-  ARGV << '--help'
-  command = ''
-else
-  command = ARGV.shift
-  command = aliases[command] || command
-end
+command = ARGV.shift
+command = aliases[command] || command
 
-require 'rails/commands/command'
+require 'rails/command'
 require 'rails/commands/dev_cache'
 
-Rails::Commands::Command.run(command, ARGV)
+Rails::Command.run(command, ARGV)

railties/lib/rails/commands/command.rb

-require 'rails/commands/commands_tasks'
-
-module Rails
-  module Commands
-    class Command
-      attr_reader :argv
-
-      def initialize(argv = [])
-        @argv = argv
-
-        @option_parser = build_option_parser
-        @options = {}
-      end
-
-      def self.run(task_name, argv)
-        command_name = command_name_for(task_name)
-
-        if command = command_for(command_name)
-          command.new(argv).run(command_name)
-        else
-          Rails::CommandsTasks.new(argv).run_command!(task_name)
-        end
-      end
-
-      def run(command_name)
-        parse_options_for(command_name)
-        @option_parser.parse! @argv
-
-        public_send(command_name)
-      end
-
-      def self.options_for(command_name, &options_to_parse)
-        @@command_options[command_name] = options_to_parse
-      end
-
-      def self.set_banner(command_name, banner)
-        options_for(command_name) { |opts, _| opts.banner = banner }
-      end
-
-      private
-        @@commands = []
-        @@command_options = {}
-
-        def parse_options_for(command_name)
-          @@command_options.fetch(command_name, proc {}).call(@option_parser, @options)
-        end
-
-        def build_option_parser
-          OptionParser.new do |opts|
-            opts.on('-h', '--help', 'Show this help.') do
-              puts opts
-              exit
-            end
-          end
-        end
-
-        def self.inherited(command)
-          @@commands << command
-        end
-
-        def self.command_name_for(task_name)
-          task_name.gsub(':', '_').to_sym
-        end
-
-        def self.command_for(command_name)
-          @@commands.find do |command|
-            command.public_instance_methods.include?(command_name)
-          end
-        end
-    end
-  end
-end

railties/lib/rails/commands/dev_cache.rb

-require 'rails/commands/command'
+require 'rails/command'
 
 module Rails
   module Commands
     # This is a wrapper around the Rails dev:cache command
     class DevCache < Command
-      set_banner :dev_cache, 'Toggle development mode caching on/off'      
+      set_banner :dev_cache, 'Toggle development mode caching on/off'
       def dev_cache
         if File.exist? 'tmp/caching-dev.txt'
           File.delete 'tmp/caching-dev.txt'