diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..3b29812
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,9 @@
+.DS_Store
+/.build
+/Packages
+/*.xcodeproj
+xcuserdata/
+DerivedData/
+.swiftpm/config/registries.json
+.swiftpm/xcode/package.xcworkspace/contents.xcworkspacedata
+.netrc
diff --git a/LICENSE b/LICENSE
new file mode 100644
index 0000000..3ebcc4b
--- /dev/null
+++ b/LICENSE
@@ -0,0 +1,21 @@
+MIT License
+
+Copyright (c) 2021 uhooi
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
diff --git a/Package.swift b/Package.swift
new file mode 100644
index 0000000..ed7d5d3
--- /dev/null
+++ b/Package.swift
@@ -0,0 +1,28 @@
+// swift-tools-version: 5.6
+// The swift-tools-version declares the minimum version of Swift required to build this package.
+
+import PackageDescription
+
+let package = Package(
+    name: "Sigmoid",
+    products: [
+        // Products define the executables and libraries a package produces, and make them visible to other packages.
+        .library(
+            name: "Sigmoid",
+            targets: ["Sigmoid"]),
+    ],
+    dependencies: [
+        // Dependencies declare other packages that this package depends on.
+        // .package(url: /* package url */, from: "1.0.0"),
+    ],
+    targets: [
+        // Targets are the basic building blocks of a package. A target can define a module or a test suite.
+        // Targets can depend on other targets in this package, and on products in packages this package depends on.
+        .target(
+            name: "Sigmoid",
+            dependencies: []),
+        .testTarget(
+            name: "SigmoidTests",
+            dependencies: ["Sigmoid"]),
+    ]
+)
diff --git a/README.md b/README.md
index 3ba7a3a..bda8e05 100644
--- a/README.md
+++ b/README.md
@@ -1,8 +1,12 @@
+[![CI](https://github.com/yoshikaz1228/Sigmoid/actions/workflows/main.yml/badge.svg?branch=main)](https://github.com/yoshikaz1228/Sigmoid/actions/workflows/main.yml)
+[![Release](https://img.shields.io/github/v/release/yoshikaz1228/Sigmoid)](https://github.com/yoshikaz1228/Sigmoid/releases/latest)
+[![License](https://img.shields.io/github/license/yoshikaz1228/Sigmoid)](https://github.com/yoshikaz1228/Sigmoid/blob/main/LICENSE)
+
 # Sigmoid
 implement sigmoid for swift.
 
 ## For example
 ```
-var sigmoid = Sigmoid()
-print(sigmoid.sigmoid(x:0.2))
+let a = 1.0
+let b = a.sigmoid()
 ```
diff --git a/Sources/Sigmoid/Sigmoid.swift b/Sources/Sigmoid/Sigmoid.swift
new file mode 100644
index 0000000..c9a4044
--- /dev/null
+++ b/Sources/Sigmoid/Sigmoid.swift
@@ -0,0 +1,13 @@
+//
+//  File.swift
+//  Sigmoid
+//
+//  Created by Yoshikaz Matsubara on 2022/08/07.
+//
+
+import Foundation
+extension Double {
+    public func sigmoid() -> Double {
+        return 1/(1+pow(M_E,-1.0 * self))
+    }
+}
diff --git a/Tests/SigmoidTests/SigmoidTests.swift b/Tests/SigmoidTests/SigmoidTests.swift
new file mode 100644
index 0000000..748fbb0
--- /dev/null
+++ b/Tests/SigmoidTests/SigmoidTests.swift
@@ -0,0 +1,18 @@
+import XCTest
+@testable import Sigmoid
+
+final class SigmoidTests: XCTestCase {
+    func testExample() throws {
+        // This is an example of a functional test case.
+        // Use XCTAssert and related functions to verify your tests produce the correct
+        // results.
+        var double: Double = 0.0
+        XCTAssertEqual(double.sigmoid(), 0.5)
+        
+        double = 1.0
+        XCTAssertEqual(double.sigmoid(), 0.7310585786300049)
+        
+        double = -1.0
+        XCTAssertEqual(double.sigmoid(), 0.2689414213699951)
+    }
+}
diff --git a/sigmoid.swift b/sigmoid.swift
deleted file mode 100644
index bbaa8cc..0000000
--- a/sigmoid.swift
+++ /dev/null
@@ -1,8 +0,0 @@
-import Foundation
-class Sigmoid {
-    init() {
-    }
-    func sigmoid(x: Double) -> Double {
-        return 1/(1+pow(M_E,-1.0 * x))
-    }
-}
diff --git a/workflows/main.yml b/workflows/main.yml
new file mode 100644
index 0000000..2e82c57
--- /dev/null
+++ b/workflows/main.yml
@@ -0,0 +1,25 @@
+name: CI
+
+on:
+  push:
+    branches: [ main ]
+  pull_request:
+    branches: [ main ]
+
+env:
+  DEVELOPER_DIR: /Applications/Xcode_13.4.1.app
+
+jobs:
+  build:
+    runs-on: macOS-latest
+    steps:
+    - uses: actions/checkout@v2
+    - name: Build
+      run: swift build -v
+
+  test:
+    runs-on: macOS-latest
+    steps:
+    - uses: actions/checkout@v2
+    - name: Test
+      run: swift test -v