update readme and gemspec

Author: KazuCocoa

README.md

@@ -1,10 +1,29 @@
 # AppiumLibCore
 
+[![Gem Version](https://badge.fury.io/rb/appium_lib_core.svg)](https://badge.fury.io/rb/appium_lib_core)
+
+# Documentation
+
+- http://www.rubydoc.info/github/appium/ruby_lib_core
+
+# base library
 - https://github.com/appium/ruby_lib
 
-[Documentation](http://www.rubydoc.info/github/appium/ruby_lib_core)
+# How to start
+## Start Appium server
+
+```bash
+$ npm install -g appium
+$ appium
+```
 
+## Run tests
 
+```bash
+$ bundle install
+$ rake test:func:android # Andorid
+$ rake test:func:ios     # iOS
+```
 
 # Release
 

appium_lib_core.gemspec

@@ -4,14 +4,16 @@ $LOAD_PATH.unshift(lib) unless $LOAD_PATH.include?(lib)
 require 'appium_lib_core/version'
 
 Gem::Specification.new do |spec|
+  spec.required_ruby_version = '>= 2.2'
+
   spec.name          = 'appium_lib_core'
   spec.version       = Appium::Core::VERSION
   spec.authors       = ['Kazuaki MATSUO']
   spec.email         = ['fly.49.89.over@gmail.com']
 
   spec.summary       = %q{Minimal Ruby library for Appium.}
   spec.description   = %q{Minimal Ruby library for Appium.}
-  spec.homepage      = 'https://github.com/appium/ruby_lib'
+  spec.homepage      = 'https://github.com/appium/ruby_lib_core/'
   spec.license       = 'Apache-2.0'
   spec.files         = `git ls-files -z`.split("\x0").reject do |f|
     f.match(%r{^(doc|test|spec|features)/})