ensure IP addresses are unique

fixes #165

app/models/ip_address.rb

@@ -15,7 +15,8 @@ class IPAddress < ApplicationRecord
 
   belongs_to :ip_pool
 
-  validates :ipv4, :presence => true
+  validates :ipv4, :presence => true, :uniqueness => true
   validates :hostname, :presence => true
+  validates :ipv6, :uniqueness => {:allow_blank => true}
 
 end