Move post replacement create action to post replacements controller.

app/views/moderator/post/posts/replace.html.erb

@@ -1,5 +0,0 @@
-<div id="c-moderator-post-posts">
-  <div id="a-replace">
-    <%= render "moderator/post/posts/replace" %>
-  </div>
-</div>

app/views/post_replacements/_new.html.erb

@@ -1,4 +1,4 @@
-<%= simple_form_for(@post, url: replace_moderator_post_post_path, method: :post) do |f| %>
+<%= simple_form_for(post_replacement, url: post_replacements_path(post_id: post_replacement.post_id), method: :post) do |f| %>
   <h1>Replace Image</h1>
 
   <p>
@@ -7,5 +7,5 @@
     lower-quality images, such as image samples, to higher-quality versions.
   </p>
 
-  <%= f.input :source, label: "New Source", input_html: { value: "" } %>
+  <%= f.input :replacement_url, label: "New Source", input_html: { value: "" } %>
 <% end %>

app/views/post_replacements/new.html.erb

@@ -0,0 +1,5 @@
+<div id="c-post-replacements">
+  <div id="a-new">
+    <%= render "new", post_replacement: @post.replacements.new %>
+  </div>
+</div>

app/views/posts/partials/show/_options.html.erb

@@ -55,7 +55,7 @@
         <li><%= link_to "Expunge", expunge_moderator_post_post_path(:post_id => post.id), :remote => true, :method => :post, :id => "expunge", :data => {:confirm => "This will permanently delete this post (meaning the file will be deleted). Are you sure you want to delete this post?"} %></li>
       <% end %>
 
-      <li><%= link_to "Replace Image", replace_moderator_post_post_path(:post_id => post.id), :id => "replace-image" %></li>
+      <li><%= link_to "Replace Image", new_post_replacement_path(:post_id => post.id), :id => "replace-image" %></li>
 
       <li id="mobile-version-list"><%= link_to "Mobile version", mobile_post_path(post) %></li>
     <% end %>

app/views/posts/show.html.erb

@@ -122,7 +122,7 @@
   </div>
 
   <div id="replace-image-dialog" class="prose" title="Replace image" style="display: none;">
-    <%= render "moderator/post/posts/replace" %>
+    <%= render "post_replacements/new", post_replacement: @post.replacements.new %>
   </div>
 
   <div id="add-to-pool-dialog" title="Add to pool" style="display: none;">