Add license, update readme and add execute bit to gradlew

LICENSE

@@ -0,0 +1,21 @@
+MIT License
+
+Copyright (c) 2023 Oskar Nordling
+
+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

@@ -15,8 +15,33 @@
 Simple and highly configurable staffchat
 
 ## Download
+
 You can download the plugin from the [Spigot resource page](https://www.spigotmc.org/resources/37804/) or via the [GitHub releases](https://github.com/oskar3123/StaffChat/releases)
 
+## License
+
+This plugin is licensed with the MIT License, for more information see the [LICENSE file](https://github.com/oskar3123/StaffChat/blob/master/LICENSE)
+
+## Building
+
+To build this yourself just clone the repository and run `build` with the Gradle Wrapper
+
+### Windows
+
+```bat
+git clone git@github.com:oskar3123/StaffChat.git
+cd StaffChat
+gradlew.bat build
+```
+
+### *nix (Linux, FreeBSD, macOS, ...)
+
+```bash
+git clone git@github.com:oskar3123/StaffChat.git
+cd StaffChat
+./gradlew build
+```
+
 ## Event API (For developers)
 
 ### Bukkit/Spigot