Invert command and commands tasks reference.

We should first attempt to run commands through Rails command, and then
fall back to trying the commands tasks.

Because eventually the commands tasks should be their own commands.

railties/lib/rails/commands.rb

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

railties/lib/rails/commands/command.rb

+require 'rails/commands/commands_tasks'
+
 module Rails
   module Commands
     class Command
@@ -15,7 +17,8 @@ def self.run(task_name, argv)
 
         if command = command_for(command_name)
           command.new(argv).run(command_name)
-          true # Indicate command was found and run.
+        else
+          Rails::CommandsTasks.new(argv).run_command!(task_name)
         end
       end
 

railties/lib/rails/commands/commands_tasks.rb

@@ -37,9 +37,7 @@ def initialize(argv)
     def run_command!(command)
       command = parse_command(command)
 
-      run_with_command = Rails::Commands::Command.run(command, argv)
-
-      if !run_with_command && COMMAND_WHITELIST.include?(command)
+      if COMMAND_WHITELIST.include?(command)
         send(command)
       end
     end