Lock gem versions and update gems

Lock to major versions for compatibility (avoiding unintentional
upgrades).

Also remove byebug from test dependencies since it exists under
development

Gemfile

@@ -4,15 +4,15 @@ ruby '2.2.3'
 gem 'dotenv-rails', groups: [:development, :test]
 gem 'rails', '~> 4.2.4'
 gem 'airbrake', '~> 5.2'
-gem 'devise'
-gem 'geokit'
-gem 'haml'
-gem 'http_accept_language'
-gem 'local_time'
+gem 'devise', '~> 3.0'
+gem 'geokit', '~> 1.0'
+gem 'haml', '~> 4.0'
+gem 'http_accept_language', '~> 2.0'
+gem 'local_time', '~> 1.0'
 gem 'obscenity', '~> 1.0', '>= 1.0.2'
 gem 'pg'
-gem 'rails_admin'
-gem 'validates_formatting_of'
+gem 'rails_admin', '~> 1.0'
+gem 'validates_formatting_of', '~> 0.9.0'
 
 gem 'tzinfo-data', platforms: [:mingw, :mswin, :x64_mingw]
 gem 'paranoia', '~> 2.2'
@@ -34,7 +34,6 @@ group :production do
 end
 
 group :test do
-  gem 'byebug'
   gem 'coveralls', require: false
   gem 'simplecov', require: false
   gem 'rubocop'