db: drop IP addresses from certain tables.

Don't track IP addresses for post appeals, post flags, tag aliases, tag
implications, or user feedbacks. These things are already tightly
limited. We don't need IPs from them to detect sockpuppets.

app/models/post_appeal.rb

@@ -3,7 +3,7 @@ class PostAppeal < ApplicationRecord
 
   belongs_to :creator, :class_name => "User"
   belongs_to :post
-  validates_presence_of :reason, :creator_ip_addr
+  validates_presence_of :reason
   validate :validate_post_is_inactive
   validate :validate_creator_is_not_limited
   before_validation :initialize_creator, :on => :create
@@ -60,7 +60,6 @@ class PostAppeal < ApplicationRecord
 
   def initialize_creator
     self.creator_id = CurrentUser.id
-    self.creator_ip_addr = CurrentUser.ip_addr
   end
 
   def appeal_count_for_creator

app/models/tag_relationship.rb

@@ -35,7 +35,6 @@ class TagRelationship < ApplicationRecord
 
   def initialize_creator
     self.creator_id = CurrentUser.user.id
-    self.creator_ip_addr = CurrentUser.ip_addr
   end
 
   def normalize_names