Update rdoc to dismiss security warnings

Gemfile

@@ -2,6 +2,7 @@ source 'https://rubygems.org'
 
 # Bundle edge Rails instead: gem 'rails', github: 'rails/rails'
 gem 'rails', '~> 4.2'
+gem 'rdoc', '~> 4.0'
 
 # Use mysql2 as the database for Active Record
 gem 'mysql2' 

Gemfile.lock

@@ -1,6 +1,6 @@
 GIT
   remote: git://github.com/activeadmin/activeadmin.git
-  revision: 6b7a77c82ce4f0a576e4397f7a86a7332c128256
+  revision: 043ba0c93408ec94e1307ad96769a3dd02334139
   specs:
     activeadmin (2.0.0.alpha)
       arbre (>= 1.1.1)
@@ -25,7 +25,7 @@ GIT
 
 GIT
   remote: git://github.com/norman/friendly_id.git
-  revision: 68cbd3d258ab301270e7e2fb3b238ead38689b34
+  revision: a29e7d7cc280d7d46c181f58fabd7cc9be67eefe
   specs:
     friendly_id (5.2.3)
       activerecord (>= 4.0.0)
@@ -120,15 +120,15 @@ GEM
     has_scope (0.7.1)
       actionpack (>= 4.1, < 5.2)
       activesupport (>= 4.1, < 5.2)
-    hashie (3.5.6)
+    hashie (3.5.7)
     http-cookie (1.0.3)
       domain_name (~> 0.5)
     i18n (0.9.1)
       concurrent-ruby (~> 1.0)
-    inherited_resources (1.7.2)
-      actionpack (>= 3.2, < 5.2.x)
+    inherited_resources (1.8.0)
+      actionpack (>= 4.2, <= 5.2)
       has_scope (~> 0.6)
-      railties (>= 3.2, < 5.2.x)
+      railties (>= 4.2, <= 5.2)
       responders
     jbuilder (2.7.0)
       activesupport (>= 4.2.0)
@@ -137,7 +137,7 @@ GEM
       rails-dom-testing (>= 1, < 3)
       railties (>= 4.2.0)
       thor (>= 0.14, < 2.0)
-    json (2.1.0)
+    json (1.8.6)
     jwt (1.5.6)
     kaminari (1.1.1)
       activesupport (>= 4.1.0)
@@ -205,8 +205,8 @@ GEM
       rack (>= 1.6.2, < 3)
     omniauth-facebook (4.0.0)
       omniauth-oauth2 (~> 1.2)
-    omniauth-oauth2 (1.4.0)
-      oauth2 (~> 1.0)
+    omniauth-oauth2 (1.5.0)
+      oauth2 (~> 1.1)
       omniauth (~> 1.2)
     orm_adapter (0.5.0)
     polyamorous (1.3.1)
@@ -227,8 +227,8 @@ GEM
       sprockets-rails
     rails-deprecated_sanitizer (1.0.3)
       activesupport (>= 4.2.0.alpha)
-    rails-dom-testing (1.0.8)
-      activesupport (>= 4.2.0.beta, < 5.0)
+    rails-dom-testing (1.0.9)
+      activesupport (>= 4.2.0, < 5.0)
       nokogiri (~> 1.6)
       rails-deprecated_sanitizer (>= 1.0.1)
     rails-html-sanitizer (1.0.3)
@@ -248,15 +248,13 @@ GEM
     rb-fsevent (0.10.2)
     rb-inotify (0.9.10)
       ffi (>= 0.5.0, < 2)
-    rdoc (3.9.5)
+    rdoc (4.3.0)
     redcarpet (3.4.0)
     ref (2.0.0)
     responders (2.4.0)
       actionpack (>= 4.2.0, < 5.3)
       railties (>= 4.2.0, < 5.3)
-    sanitize (2.1.0)
-      nokogiri (>= 1.4.4)
-    sass (3.5.3)
+    sass (3.5.4)
       sass-listen (~> 4.0.0)
     sass-listen (4.0.0)
       rb-fsevent (~> 0.9, >= 0.9.4)
@@ -267,10 +265,9 @@ GEM
       sprockets (>= 2.8, < 4.0)
       sprockets-rails (>= 2.0, < 4.0)
       tilt (>= 1.1, < 3)
-    sdoc (0.3.11)
-      json (>= 1.1.3)
-      rdoc (~> 3)
-      sanitize (~> 2)
+    sdoc (0.4.2)
+      json (~> 1.7, >= 1.7.7)
+      rdoc (~> 4.0)
     sprockets (3.6.3)
       concurrent-ruby (~> 1.0)
       rack (> 1, < 3)
@@ -292,7 +289,7 @@ GEM
       thread_safe (~> 0.1)
     tzinfo-data (1.2017.3)
       tzinfo (>= 1.0.0)
-    uglifier (3.2.0)
+    uglifier (4.0.2)
       execjs (>= 0.3.0, < 3)
     unf (0.1.4)
       unf_ext
@@ -328,6 +325,7 @@ DEPENDENCIES
   omniauth
   omniauth-facebook
   rails (~> 4.2)
+  rdoc (~> 4.0)
   redcarpet
   sass-rails
   sdoc
@@ -338,4 +336,4 @@ DEPENDENCIES
   uglifier
 
 BUNDLED WITH
-   1.16.0
+   1.16.1