add Package.swift, fix Interface Builder render error

.gitignore

@@ -0,0 +1,2 @@
+Example/Pods
+

BatteryView.podspec

@@ -19,7 +19,7 @@ batteryView.level = 42 // anywhere in 0...100
   s.license      = { :type => "MIT", :file => "LICENSE.txt" }
 
   s.author             = { "Yonat Sharon" => "yonat@ootips.org" }
-  s.social_media_url   = "http://twitter.com/yonatsharon"
+  s.social_media_url   = "https://twitter.com/yonatsharon"
 
   s.swift_version = '4.2'
   s.swift_versions = ['4.2', '5.0']
@@ -28,4 +28,7 @@ batteryView.level = 42 // anywhere in 0...100
 
   s.source       = { :git => "https://github.com/yonat/BatteryView.git", :tag => s.version }
   s.source_files  = "Sources/*"
+
+  s.pod_target_xcconfig = { 'LD_RUNPATH_SEARCH_PATHS' => '$(FRAMEWORK_SEARCH_PATHS)' } # fix Interface Builder render error
+
 end

CHANGELOG.md

@@ -4,6 +4,14 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](http://keepachangelog.com/en/1.0.0/)
 and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.html).
 
+## [Unreleased]
+
+### Added
+- support Swift Package Manager.
+
+### Fixed
+- fix Interface Builder render error.
+
 ## [1.3.7] - 2019-07-13
 
 ### Added

Package.swift

@@ -0,0 +1,18 @@
+// swift-tools-version:5.1
+
+import PackageDescription
+
+let package = Package(
+    name: "BatteryView",
+    platforms: [
+        .iOS(.v9)
+    ],
+    products: [
+        .library( name: "BatteryView", targets: ["BatteryView"])
+    ],
+    dependencies: [],
+    targets: [
+        .target(name: "BatteryView", dependencies: [], path: "Sources")
+    ],
+    swiftLanguageVersions: [.v5]
+)