Add add_handler macro

spec/config_spec.cr

@@ -1,11 +1,5 @@
 require "./spec_helper"
 
-class CustomTestHandler < HTTP::Handler
-  def call(request)
-    call_next request
-  end
-end
-
 describe "Config" do
   it "sets default port to 3000" do
     config = Kemal.config

spec/macros_spec.cr

@@ -14,4 +14,11 @@ describe "Macros" do
       Kemal.config.public_folder.should eq("/some/path/to/folder")
     end
   end
+
+  describe "#add_handler" do
+    it "adds a custom handler" do
+      add_handler CustomTestHandler.new
+      Kemal.config.handlers.size.should eq 1
+    end
+  end
 end

spec/spec_helper.cr

@@ -4,6 +4,12 @@ require "../src/kemal/middleware/*"
 
 include Kemal
 
+class CustomTestHandler < HTTP::Handler
+  def call(request)
+    call_next request
+  end
+end
+
 Spec.before_each do
   Kemal.config.env = "development"
   Kemal.config.handlers.clear