rename Ledger to Book

lib/gnucash.rb

@@ -1,8 +1,8 @@
-require "gnucash/ledger"
+require "gnucash/book"
 require "gnucash/version"
 
 module Gnucash
   def self.open(fname)
-    Ledger.new(fname)
+    Book.new(fname)
   end
 end

lib/gnucash/book.rb

@@ -2,7 +2,7 @@ require "zlib"
 require "nokogiri"
 
 module Gnucash
-  class Ledger
+  class Book
     def initialize(fname)
       @ng = Nokogiri.XML(Zlib::GzipReader.open(fname).read)
     end