我有一个 rails 项目，我想添加一个新表并在项目中已经存在的一个表中进行更改。从终端和现有 rails 项目的文件夹中，我写了这个：
Mini-1:arbinet anna$ rails generate model PriceRate profitable_routes_id:int normalized_rate:float normalized_payout:float margin:float old_rate:float old_payout:float old_margin:float
这也适用于迁移：
Mini-1:arbinet anna$ rails generate migration ChangeColumnsFromProfitableRoutes
但对于两者，我都会收到以下信息：
Usage:
rails new APP_PATH [options]
Options:
-r, [--ruby=PATH] # Path to the Ruby binary of your choice
# Default: /Users/anna/.rvm/rubies/ruby-1.9.3-p286/bin/ruby
-b, [--builder=BUILDER] # Path to a application builder (can be a filesystem path or URL)
-m, [--template=TEMPLATE] # Path to an application template (can be a filesystem path or URL)
[--skip-gemfile] # Don't create a Gemfile
[--skip-bundle] # Don't run bundle install
-G, [--skip-git] # Skip Git ignores and keeps
-O, [--skip-active-record] # Skip Active Record files
-S, [--skip-sprockets] # Skip Sprockets files
-d, [--database=DATABASE] # Preconfigure for selected database (options: mysql/oracle/postgresql/sqlite3/frontbase/ibm_db/sqlserver/jdbcmysql/jdbcsqlite3/jdbcpostgresql/jdbc)
# Default: sqlite3
-j, [--javascript=JAVASCRIPT] # Preconfigure for selected JavaScript library
# Default: jquery
-J, [--skip-javascript] # Skip JavaScript files
[--dev] # Setup the application with Gemfile pointing to your Rails checkout
[--edge] # Setup the application with Gemfile pointing to Rails repository
-T, [--skip-test-unit] # Skip Test::Unit files
[--old-style-hash] # Force using old style hash (:foo => 'bar') on Ruby >= 1.9
Runtime options:
-f, [--force] # Overwrite files that already exist
-p, [--pretend] # Run but do not make any changes
-q, [--quiet] # Suppress status output
-s, [--skip] # Skip files that already exist
Rails options:
-h, [--help] # Show this help message and quit
-v, [--version] # Show Rails version number and quit
Description:
The 'rails new' command creates a new Rails application with a default
directory structure and configuration at the path you specify.
You can specify extra command-line arguments to be used every time
'rails new' runs in the .railsrc configuration file in your home directory.
Note that the arguments specified in the .railsrc file don't affect the
defaults values shown above in this help message.
Example:
rails new ~/Code/Ruby/weblog
This generates a skeletal Rails installation in ~/Code/Ruby/weblog.
See the README in the newly created application to get going.
而且我不知道为什么，但是当我创建其他表时它正在工作。