fix: Gemfile.lock & Gemfile to reduce vulnerabilities

The following vulnerabilities are fixed with an upgrade:
- https://snyk.io/vuln/SNYK-RUBY-SPROCKETS-22032

Gemfile

@@ -25,10 +25,10 @@ gem 'rails', '4.2.10'
 gem 'rails-i18n'
 gem 'ransack'
 gem 'rubytree'
-gem 'sass-rails'
+gem 'sass-rails', '>= 5.0.7'
 gem 'sdoc', group: :doc
 gem 'slim-rails'
-gem 'bootstrap_pagedown'
+gem 'bootstrap_pagedown', '>= 1.1.0'
 gem 'pagedown-rails'
 gem 'sorcery'
 gem 'thread_safe'

Gemfile.lock

@@ -108,7 +108,7 @@ GEM
     concurrent-ruby (1.0.5)
     concurrent-ruby-ext (1.0.5)
       concurrent-ruby (= 1.0.5)
-    crass (1.0.3)
+    crass (1.0.4)
     d3-rails (4.13.0)
       railties (>= 3.1)
     database_cleaner (1.6.2)
@@ -135,7 +135,7 @@ GEM
     faye-websocket (0.10.7)
       eventmachine (>= 0.12.0)
       websocket-driver (>= 0.5.1)
-    ffi (1.9.23)
+    ffi (1.9.25)
     forgery (0.7.0)
     globalid (0.4.1)
       activesupport (>= 4.2.0)
@@ -161,7 +161,7 @@ GEM
     json (2.1.0)
     jwt (1.5.6)
     kramdown (1.16.2)
-    loofah (2.2.0)
+    loofah (2.2.2)
       crass (~> 1.0.2)
       nokogiri (>= 1.5.9)
     mail (2.7.0)
@@ -181,7 +181,7 @@ GEM
     net-ssh (4.2.0)
     netrc (0.11.0)
     newrelic_rpm (4.8.0.341)
-    nokogiri (1.8.2)
+    nokogiri (1.8.3)
       mini_portile2 (~> 2.3.0)
     nyan-cat-formatter (0.12.0)
       rspec (>= 2.99, >= 2.14.2, < 4)
@@ -211,7 +211,7 @@ GEM
     puma (3.11.3)
     pundit (1.1.0)
       activesupport (>= 3.0.0)
-    rack (1.6.9)
+    rack (1.6.10)
     rack-mini-profiler (0.10.7)
       rack (>= 1.2.0)
     rack-test (0.6.3)
@@ -233,8 +233,8 @@ GEM
       activesupport (>= 4.2.0, < 5.0)
       nokogiri (~> 1.6)
       rails-deprecated_sanitizer (>= 1.0.1)
-    rails-html-sanitizer (1.0.3)
+    rails-html-sanitizer (1.0.4)
-      loofah (~> 2.0)
+      loofah (~> 2.2, >= 2.2.2)
     rails-i18n (4.0.9)
       i18n (~> 0.7)
       railties (~> 4.0)
@@ -244,7 +244,7 @@ GEM
       rake (>= 0.8.7)
       thor (>= 0.18.1, < 2.0)
     rainbow (3.0.0)
-    rake (12.3.0)
+    rake (12.3.1)
     ransack (1.8.7)
       actionpack (>= 3.0)
       activerecord (>= 3.0)
@@ -296,7 +296,7 @@ GEM
       json (~> 2.1)
       structured_warnings (~> 0.3)
     rubyzip (1.2.1)
-    sass (3.5.5)
+    sass (3.5.6)
       sass-listen (~> 4.0.0)
     sass-listen (4.0.0)
       rb-fsevent (~> 0.9, >= 0.9.4)
@@ -330,7 +330,7 @@ GEM
       oauth2 (~> 1.0, >= 0.8.0)
     spring (2.0.2)
       activesupport (>= 4.2)
-    sprockets (3.7.1)
+    sprockets (3.7.2)
       concurrent-ruby (~> 1.0)
       rack (> 1, < 3)
     sprockets-rails (3.2.1)
@@ -383,7 +383,7 @@ DEPENDENCIES
   better_errors
   binding_of_caller
   bootstrap-will_paginate
-  bootstrap_pagedown
+  bootstrap_pagedown (>= 1.1.0)
   byebug
   capistrano
   capistrano-rails
@@ -430,7 +430,7 @@ DEPENDENCIES
   rubocop-rspec
   rubytree
   rubyzip
-  sass-rails
+  sass-rails (>= 5.0.7)
   sdoc
   simplecov
   slim-rails