added sanitize initializer

config/initializers/sanitize.rb

@@ -0,0 +1,9 @@
+EVIL_TAGS = {
+  elements: %w(quote a p i strong em del pre code table tr td th br ul ol li hr),
+  attributes: {
+    'a' => %w(href)
+  },
+  protocols: {
+    'a' => { 'href' => ['http', 'https', :relative] }
+  }
+}