wiki pages: drop creator and updater fields.

Drop the creator_id and updater_id fields from wiki pages. These fields
had several issues:

* The creator_id field was inconsistent with the wiki_page_versions
  table. Apparently during the migration to Danbooru 2 in 2012-2013 the
  creator_id field got reset to whoever last updated the wiki at that
  point in time.

* Saving a wiki would set the updater_id even when nothing actually
  changed. This also caused the updated_at timestamp to get bumped.
  Because of this, anything that saved a wiki, including things like
  creating aliases or implications, would bump the updater_id and
  updated_at even though the wiki didn't actually change. This meant
  these fields weren't consistent with the wiki_page_versions history.

Changes:

* Remove `creator_name` field from the /wiki_pages.json API.
* Remove creator name search option from /wiki_pages/search.

app/controllers/wiki_pages_controller.rb

@@ -16,7 +16,7 @@ class WikiPagesController < ApplicationController
   end
 
   def index
-    @wiki_pages = WikiPage.includes(:creator).paginated_search(params)
+    @wiki_pages = WikiPage.paginated_search(params)
     respond_with(@wiki_pages) do |format|
       format.html do
         if params[:page].nil? || params[:page].to_i == 1

app/models/wiki_page.rb

@@ -15,14 +15,12 @@ class WikiPage < ApplicationRecord
 
   attr_accessor :skip_secondary_validations
   array_attribute :other_names
-  belongs_to_creator
-  belongs_to_updater
   has_one :tag, :foreign_key => "name", :primary_key => "title"
   has_one :artist, -> {where(:is_active => true)}, :foreign_key => "name", :primary_key => "title"
   has_many :versions, -> {order("wiki_page_versions.id ASC")}, :class_name => "WikiPageVersion", :dependent => :destroy
   has_many :dtext_links, as: :model, dependent: :destroy
 
-  api_attributes including: [:creator_name, :category_name]
+  api_attributes including: [:category_name]
 
   module SearchMethods
     def titled(title)
@@ -63,7 +61,7 @@ class WikiPage < ApplicationRecord
     def search(params = {})
       q = super
 
-      q = q.search_attributes(params, :creator, :updater, :is_locked, :is_deleted, :body)
+      q = q.search_attributes(params, :is_locked, :is_deleted, :body)
       q = q.text_attribute_matches(:body, params[:body_matches], index_column: :body_index, ts_config: "danbooru")
 
       if params[:title].present?
@@ -102,10 +100,6 @@ class WikiPage < ApplicationRecord
     end
   end
 
-  def creator_name
-    creator.name
-  end
-
   extend SearchMethods
 
   def validate_not_locked

app/views/wiki_pages/index.html.erb

@@ -14,7 +14,7 @@
       <% @wiki_pages.each do |wiki_page| %>
         <tr>
           <td class="category-<%= wiki_page.category_name %>"><%= link_to wiki_page.pretty_title, wiki_page_path(wiki_page, :noredirect => 1) %></td>
-          <td><%= wiki_page.updated_at.strftime("%Y-%m-%d %H:%M") %> by <%= h link_to_user wiki_page.updater %></td>
+          <td><%= time_ago_in_words_tagged(wiki_page.updated_at) %></td>
         </tr>
       <% end %>
     </tbody>

app/views/wiki_pages/search.html.erb

@@ -3,7 +3,6 @@
     <%= search_form_for(wiki_pages_path) do |f| %>
       <%= f.input :title, hint: "Use * for wildcard searches", input_html: { "data-autocomplete": "wiki-page" } %>
       <%= f.input :other_names_match, label: "Other names", hint: "Use * for wildcard searches" %>
-      <%= f.input :creator_name, input_html: { "data-autocomplete": "user" } %>
       <%= f.input :body_matches, label: "Body" %>
       <%= f.input :other_names_present, as: :select %>
       <%= f.input :hide_deleted, as: :select, include_blank: false %>