I've been using rails more often now; however, I still google lots of basic stuff :) this is my personal cheat sheet, but might be also useful to others. I will be adding more as time goes on.
ActiveRecord Datatypes
:binary, :primary_key
:boolean
:date, :datetime, :time:timestamp
:decimal, :float, :integer
:string, :text
Relationships: :belongs_to, :has_one, :has_many (still need to add FK fields)