Coding convention as on ruby on rails development

As suggested by ruby on rails framework development:

Follow the Coding Conventions
Rails follows a simple set of coding style conventions.

• Two spaces, no tabs (for indentation).
• No trailing whitespace. Blank lines should not have any spaces.
• Indent after private/protected.
• Prefer &&/|| over and/or.
• Prefer class << self over self.method for class methods.
• Use MyClass.my_method(my_arg) not my_method( my_arg ) or my_method my_arg.
• Use a = b and not a=b.
• Follow the conventions in the source you see used already.
• The above are guidelines — please use your best judgment in using them.

reference: http://guides.rubyonrails.org/contributing_to_ruby_on_rails.html#follow-the-coding-conventions