FEATURE: add censored_pattern setting to censor posts using regex

lib/validators/regex_setting_validator.rb

@@ -0,0 +1,25 @@
+class RegexSettingValidator
+
+  LOREM = 'Lorem ipsum dolor sit amet, consectetur adipiscing elit. Nullam eget sem non elit tincidunt rhoncus.'.freeze
+
+  def initialize(opts={})
+    @opts = opts
+  end
+
+  def valid_value?(val)
+    !val.present? || valid_regex?(val)
+  end
+
+  # Check that string is a valid regex, and that it doesn't match most of the lorem string.
+  def valid_regex?(val)
+    r = Regexp.new(val)
+    matches = r.match(LOREM)
+    matches.nil? || matches[0].length < (LOREM.length - 10)
+  rescue
+    false
+  end
+
+  def error_message
+    I18n.t('site_settings.errors.invalid_regex')
+  end
+end