diff --git a/app/models/qbo_estimate.rb b/app/models/qbo_estimate.rb
index 1985a5b..d974e37 100644
--- a/app/models/qbo_estimate.rb
+++ b/app/models/qbo_estimate.rb
@@ -1,6 +1,6 @@
 #The MIT License (MIT)
 #
-#Copyright (c) 2016 rick barrette
+#Copyright (c) 2017 rick barrette
 #
 #Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
 #
@@ -10,47 +10,49 @@
 
 class QboEstimate < ActiveRecord::Base
   unloadable
-  has_many :issues
-  belongs_to :customer 
-  attr_accessible :doc_number
-  validates_presence_of :id, :doc_number, :customer_id
   
+  has_and_belongs_to_many :issues
+  belongs_to :customer 
+  attr_accessible :doc_number, :id
+  validates_presence_of :doc_number, :id
+  self.primary_key = :id
+  
+  # return the QBO Estimate service
   def self.get_base
-    Qbo.get_base(:estimate)
+    Qbo.get_base(:estimate).service
   end
   
+  # sync all estimates
   def self.sync 
-    estimates = get_base.service.all
-  
-    # Update the item table
-    transaction do
-        estimates.each { |estimate|
-          qbo_estimate = QboEstimate.find_or_create_by(id: estimate.id)
-          qbo_estimate.doc_number = estimate.doc_number
-          qbo_estimate.customer_id = estimate.customer_ref.value
-          qbo_estimate.id = estimate.id
-          qbo_estimate.save!
-        }
-    end
-    
+    estimates = get_base.all
+    estimates.each { |estimate|
+      process_estimate(estimate)
+    }
+
     #remove deleted estimates
     where.not(estimates.map(&:id)).destroy_all
   end
   
+  # sync only one estimate
   def self.sync_by_id(id)
-    estimate = get_base.service.fetch_by_id(id)
-    qbo_estimate = QboEstimate.find_or_create_by(id: estimate.id)
+    process_estimate(get_base.fetch_by_id(id))
+  end
+  
+  # update an estimate
+  def self.update(id)
+    # Update the item table
+    estimate = get_base.fetch_by_id(id)
+    qbo_estimate = find_or_create_by(id: id)
+    qbo_estimate.doc_number = estimate.doc_number
+    qbo_estimate.save!
+  end
+  
+  # process an estimate into the database
+  def process_estimate(estimate)
+    qbo_estimate = find_or_create_by(id: estimate.id)
     qbo_estimate.doc_number = estimate.doc_number
     qbo_estimate.customer_id = estimate.customer_ref.value
     qbo_estimate.id = estimate.id
     qbo_estimate.save!
   end
-  
-  def self.update(id)
-    # Update the item table
-    estimate = get_base.service.fetch_by_id(id)
-      qbo_estimate = QboEstimate.find_or_create_by(id: id)
-      qbo_estimate.doc_number = estimate.doc_number
-      qbo_estimate.save!
-  end
 end