Adding method for doing browser redirection from inside any route.

Made some small changes

README.md

@@ -119,6 +119,17 @@ Accessing the environment (query params, body, content_type, headers, status_cod
   end
 ```
 
+### Browser Redirect
+Just like other things in `kemal`, browser redirection is super simple as well. Use `environment` variable in defined route's corresponding block and call `redirect` on it.
+
+```ruby
+  # Redirect browser
+  get "/logout" do |env|
+	# important stuff like clearing session etc.
+	env.redirect "/login" # redirect to /login page
+  end
+```
+
 ## Middlewares
 
 You can create your own middlewares by inheriting from ```HTTP::Handler```

spec/kemal_handler_spec.cr

@@ -184,4 +184,15 @@ describe "Kemal::Handler" do
     response.status_code.should eq(404)
   end
 
+  it "redirects user to provided url" do
+    kemal = Kemal::Handler.new
+    kemal.add_route "GET", "/" do |env|
+      env.redirect("/login")
+    end
+    request = HTTP::Request.new("GET", "/")
+    response = kemal.call(request)
+    response.status_code.should eq(301)
+    response.headers.has_key?("Location").should eq(true)
+  end
+
 end

src/kemal/context.cr

@@ -22,6 +22,11 @@ class Kemal::Context
     @response.content_type
   end
 
+  def redirect(url)
+    @response.headers.add "Location", url
+    @response.status_code = 301
+  end
+
   delegate headers, @request
   delegate status_code, @response
   delegate :"status_code=", @response