Add render macro to kemal core to have dynamic rendering mechanism. It actually binds built-in ecr parser to the Kemal as a macro.

src/kemal/view.cr

@@ -0,0 +1,14 @@
+# Kemal render uses built-in ECR to render methods.
+
+## Usage
+# get '/' do
+#   render 'hello.ecr'
+# end
+
+require "ecr/macros"
+
+macro render(filename)
+  String.build do |__view__|
+    embed_ecr {{filename}}, "__view__"
+  end
+end