if you itterate through a list of words, you need to do like that:
require 'sinatra'
require 'csv'
require 'data_mapper'
DataMapper::setup(:default, "sqlite3://#{Dir.pwd}/scrabble.db")
class Letters
include DataMapper::Resource
property :id, Serial
property :content, Text, :required => true
property :created_at, DateTime
property :updated_at, DateTime
end
CSV.foreach("words.txt") do |row|
Letters.create(content: row[0])
end