Customise slug base name for different models

fixes #2480

- when the santisation of a slug results in an empty string, we use a basename instead.
- this was 'post' and is now the table name for the model, minus the trailing 's'
- this isn't massively robust but works as a temporary fix

core/server/models/base.js

@@ -199,7 +199,10 @@ ghostBookshelf.Model = ghostBookshelf.Model.extend({
     generateSlug: function (Model, base, readOptions) {
         var slug,
             slugTryCount = 1,
+            baseName = Model.prototype.tableName.replace(/s$/, ''),
             // Look for a post with a matching slug, append an incrementing number if so
+            checkIfSlugExists;
+
         checkIfSlugExists = function (slugToFind) {
             var args = {slug: slugToFind};
             //status is needed for posts
@@ -249,11 +252,11 @@ ghostBookshelf.Model = ghostBookshelf.Model.extend({
 
         // Check the filtered slug doesn't match any of the reserved keywords
         slug = /^(ghost|ghost\-admin|admin|wp\-admin|wp\-login|dashboard|logout|login|signin|signup|signout|register|archive|archives|category|categories|tag|tags|page|pages|post|posts|user|users|rss)$/g
-            .test(slug) ? slug + '-post' : slug;
+            .test(slug) ? slug + '-' + baseName : slug;
 
         //if slug is empty after trimming use "post"
         if (!slug) {
-            slug = 'post';
+            slug = baseName;
         }
         // Test for duplicate slugs.
         return checkIfSlugExists(slug);