Update rails-observers dependency.

Author: Daniel P. Shannon

Gemfile

@@ -1,6 +1,7 @@
 source 'https://rubygems.org'
 
 gem 'mongoid',          '~> 5.1.2'
+gem 'rails-observers',  github: 'rails/rails-observers'
 gem 'rake',             '~> 10.4.2'
 gem 'rspec',            '~> 3.1.0'
 gem 'guard-rspec',      '~> 4.6.4'
@@ -11,4 +12,4 @@ gem 'codeclimate-test-reporter'
 gem 'railties'
 
 # Specify your gem's dependencies in mongoid-observers.gemspec
-gemspec
+gemspec

mongoid-observers.gemspec

@@ -18,7 +18,6 @@ Gem::Specification.new do |spec|
   spec.test_files    = spec.files.grep(%r{^(test|spec|features)/})
   spec.require_paths = ["lib"]
 
-  spec.add_dependency "rails-observers", "~> 0.1.2"
   spec.add_dependency "mongoid", ">= 4.0.0"
 
   spec.add_development_dependency "ammeter", "~> 1.1.2"