Update details in gemspec

and increase version

lib/panko/version.rb

@@ -1,5 +1,5 @@
 # frozen_string_literal: true
 
 module Panko
-  VERSION = "0.5.8"
+  VERSION = "0.5.9"
 end

panko_serializer.gemspec

@@ -1,6 +1,6 @@
-# coding: utf-8
 # frozen_string_literal: true
-lib = File.expand_path("../lib", __FILE__)
+
+lib = File.expand_path("lib", __dir__)
 $LOAD_PATH.unshift(lib) unless $LOAD_PATH.include?(lib)
 require "panko/version"
 
@@ -10,11 +10,20 @@ Gem::Specification.new do |spec|
   spec.authors       = ["Yosi Attias"]
   spec.email         = ["yosy101@gmail.com"]
 
-  spec.summary       = "Fast serialization for ActiveModel"
-  spec.homepage      = ""
+  spec.summary       = "High Performance JSON Serialization for ActiveRecord & Ruby Objects"
+  spec.homepage      = "https://yosiat.github.io/panko_serializer/"
   spec.license       = "MIT"
 
-  spec.files         = `git ls-files -z`.split("\x0").reject do |f|
+  spec.metadata = {
+    "bug_tracker_uri" => "https://github.com/yosiat/panko_serializer/issues",
+    "source_code_uri" => "https://github.com/yosiat/panko_serializer",
+    "documentation_uri" => "https://yosiat.github.io/panko_serializer/",
+    "changelog_uri" => "https://github.com/yosiat/panko_serializer/releases"
+  }
+
+  spec.required_ruby_version = ">= 2.0"
+
+  spec.files = `git ls-files -z`.split("\x0").reject do |f|
     f.match(%r{^(test|spec|features)/})
   end
   spec.require_paths = ["lib"]