[Snyk] Fix for 54 vulnerabilities

Gemfile

@@ -1,26 +1,26 @@
 source 'https://rubygems.org'
 
 # TODO: rails 4.2
-gem 'rails', '5.2.6.2'
-gem 'jquery-rails', '>= 4.0.1'
+gem 'rails', '6.1.7.3'
+gem 'jquery-rails', '>= 4.4.0'
 gem 'rails_autolink', '>= 1.1.6'
 
 gem 'qiita-markdown', :platforms => :ruby
-gem 'kramdown',       :platforms => :jruby
+gem 'kramdown', '>= 2.3.0', :platforms => :jruby
 
-gem 'omniauth-openid'
+gem 'omniauth-openid', '>= 2.0.1'
 gem 'erubis'
-gem 'kaminari', '>= 0.16.1'
+gem 'kaminari', '>= 1.2.1'
 
-gem 'simple_form', '>= 4.0.0'
+gem 'simple_form', '>= 5.0.0'
 
 gem 'coveralls', require: false
 
 gem 'pg', group: :postgresql
 
 group :development do
   # better_errors 2.0 requires Ruby 2.0 or higher
-  gem 'better_errors', '1.1.0'
+  gem 'better_errors', '2.8.0'
   gem 'magic_encoding'
   gem 'binding_of_caller', :platforms => :ruby
 end
@@ -44,16 +44,16 @@ end
 
 group :assets do
   gem 'less-rails', '>= 2.6.0'
-  gem 'twitter-bootstrap-rails', '>= 2.2.8'
+  gem 'twitter-bootstrap-rails', '>= 3.2.0'
   gem 'therubyracer', :platforms => :ruby
   gem 'therubyrhino', :platforms => :jruby
-  gem 'uglifier', '>= 1.0.3'
+  gem 'uglifier', '>= 2.7.2'
 end
 
 group :server do
   # bin/rails s mizuno
   gem 'mizuno', :platforms => :jruby
-  gem 'thin', :platforms => :ruby
+  gem 'thin', '>= 1.7.0', :platforms => :ruby
 end
 
 # rails g rspec:install