if coauthor not in coauthor db then it will be add in db

app/models/user/co_author.rb

@@ -9,11 +9,12 @@ class CoAuthor
   field :type
 
 
-  VALID_EMAIL_REGEX = /\A[\w+\-.]+@[a-z\d\-.]+\.[a-z]+\z/i
+  VALID_EMAIL_REGEX = /\A[\w+\-.]+@[a-z\d\-.]+\.[a-z]+\z/
   validates :email, format: { with: VALID_EMAIL_REGEX },
+            allow_blank: true,
              uniqueness: { case_sensitive: false }
 
   validates :co_author, presence: true
-  before_save { |coauthor| coauthor.email = email.downcase }
+  before_save { |coauthor| coauthor.email = email.downcase if not coauthor.email.nil?}
 end
 

vendor/built_in_modules/personal_journal/app/models/writing_journal.rb

@@ -35,9 +35,26 @@ class WritingJournal
   accepts_nested_attributes_for :writing_journal_files, :allow_destroy => true
   after_save :save_writing_journal_files
   before_validation :add_http
+  before_save :save_co_author
   validates :paper_title, :at_least_one => true
   validates :url, :format => /^(http|https):\/\/[a-z0-9]+([\-\.]{1}[a-z0-9]+)*\.[a-z]{2,5}(([0-9]{1,5})?\/.*)?$/ix, :unless => Proc.new{self.url.blank?}
 
+  def save_co_author
+    authors_list = authors.split(",").map{|n| n.strip.gsub(/\s+/," ")}.reject{|n| n.empty? }
+    if new_record?
+      current_user = create_user_id
+    else
+      current_user = update_user_id
+    end
+
+    authors_db = CoAuthor.where(:name_id => current_user).map(&:co_author)
+    authors_list.delete(User.find(current_user).name)
+    authors_list = authors_list.delete_if{|author| authors_db.include?author}
+    authors_list.each do |author|
+      CoAuthor.new(:co_author => author, :name_id => current_user).save
+    end
+  end
+
   def self.search( category_id = nil )
     if category_id.to_s.size > 0
       find(:all, :conditions => {writing_journal_category_id: category_id}).desc( :is_top, :title )