Add a license and readme file

LICENSE

@@ -0,0 +1,21 @@
+MIT License
+
+Copyright (c) 2021 Marcel Voss
+
+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.

README.md

@@ -1,3 +1,38 @@
 # Base62
+[![CI](https://github.com/marcelvoss/Base62/actions/workflows/ci.yml/badge.svg?branch=main)](https://github.com/marcelvoss/Base62/actions/workflows/ci.yml)
 
-A description of this package.
+Base62 is a tiny package for [Base62](https://en.wikipedia.org/wiki/Base62) encoding/decoding values. It is tested, documented, easy-to-use and supports Apple Platforms, as well as Linux.
+
+## Installation
+Base62 is distributed using the Swift Package Manager. To install it into a project, add it as a dependency within your `Package.swift` manifest:
+
+```swift
+let package = Package(
+    ...
+    dependencies: [
+        .package(url: "https://github.com/marcelvoss/Base62.git", from: "0.1.0")
+    ],
+    ...
+)
+```
+
+Then import Base62 wherever you’d like to use it:
+
+```swift
+import Base62
+```
+
+## Usage
+Using Base62 is incredibly easy, as it focusses on a single responsibility and does that nicely.
+
+Base62 ships with a single object that provides encoding and decoding functionality.
+
+```swift
+let base62Encoded = Base62.encode(2021)
+// 2021 == "wz"
+
+let base62Decoded = Base62.decode("GitHub")
+// "GitHub" == 38750631667
+```
+
+There are also extensions for `String` and `Int` available, if you prefer to use them rather than the `Base62` object directly.