Auto include middleware for older railses

README.md

@@ -71,12 +71,7 @@ Or install it yourself as:
 
 Then tell your ruby web application to use rack-attack as a middleware.
 
-a) For __rails__ applications with versions >= 5.1 it is used by default. For older rails versions you should enable it explicitly:
-```ruby
-# In config/application.rb
-
-config.middleware.use Rack::Attack
-```
+a) For __rails__ applications it is used by default.
 
 You can disable it permanently (like for specific environment) or temporarily (can be useful for specific test cases) by writing:
 

lib/rack/attack/railtie.rb

@@ -4,9 +4,7 @@ module Rack
   class Attack
     class Railtie < ::Rails::Railtie
       initializer "rack-attack.middleware" do |app|
-        if Gem::Version.new(::Rails::VERSION::STRING) >= Gem::Version.new("5.1")
-          app.middleware.use(Rack::Attack)
-        end
+        app.middleware.use(Rack::Attack)
       end
     end
   end

spec/acceptance/rails_middleware_spec.rb

@@ -12,24 +12,9 @@ if defined?(Rails)
       end
     end
 
-    if Gem::Version.new(Rails::VERSION::STRING) >= Gem::Version.new("5.1")
-      it "is used by default" do
-        @app.initialize!
-        assert_equal 1, @app.middleware.count(Rack::Attack)
-      end
-
-      it "is not added when it was explicitly deleted" do
-        @app.config.middleware.delete(Rack::Attack)
-        @app.initialize!
-        refute @app.middleware.include?(Rack::Attack)
-      end
-    end
-
-    if Gem::Version.new(Rails::VERSION::STRING) < Gem::Version.new("5.1")
-      it "is not used by default" do
-        @app.initialize!
-        assert_equal 0, @app.middleware.count(Rack::Attack)
-      end
+    it "is used by default" do
+      @app.initialize!
+      assert @app.middleware.include?(Rack::Attack)
     end
   end
 end