Follow advisory: Add license, DCO and contributing

Signed-off-by: Steven Kriegler <61625851+justusbunsi@users.noreply.github.com>

CONTRIBUTING.md

@@ -0,0 +1,22 @@
+# Contribution Guidelines
+
+## Table of Contents
+
+- [Contribution Guidelines](#contribution-guidelines)
+    - [Developer Certificate of Origin (DCO)](#developer-certificate-of-origin-dco)
+
+
+## Developer Certificate of Origin (DCO)
+
+I consider the act of contributing to the code by submitting a Pull Request as the "Sign off" or agreement to the 
+certifications and terms of the [DCO](DCO) and [MIT license](LICENSE). No further action is required. Additionally, 
+you could add a line at the end of your commit message.
+
+```
+Signed-off-by: Joe Smith <joe.smith@email.com>
+```
+
+If you set your `user.name` and `user.email` git configs, you can add the line to the end of your commit automatically 
+with `git commit -s`.
+
+I assume in good faith that the information you provide is legally binding.

DCO

@@ -0,0 +1,37 @@
+Developer Certificate of Origin
+Version 1.1
+
+Copyright (C) 2004, 2006 The Linux Foundation and its contributors.
+1 Letterman Drive
+Suite D4700
+San Francisco, CA, 94129
+
+Everyone is permitted to copy and distribute verbatim copies of this
+license document, but changing it is not allowed.
+
+
+Developer's Certificate of Origin 1.1
+
+By making a contribution to this project, I certify that:
+
+(a) The contribution was created in whole or in part by me and I
+    have the right to submit it under the open source license
+    indicated in the file; or
+
+(b) The contribution is based upon previous work that, to the best
+    of my knowledge, is covered under an appropriate open source
+    license and I have the right under that license to submit that
+    work with modifications, whether created in whole or in part
+    by me, under the same open source license (unless I am
+    permitted to submit under a different license), as indicated
+    in the file; or
+
+(c) The contribution was provided directly to me by some other
+    person who certified (a), (b) or (c) and I have not modified
+    it.
+
+(d) I understand and agree that this project and the contribution
+    are public and that a record of the contribution (including all
+    personal information I submit with it, including my sign-off) is
+    maintained indefinitely and may be redistributed consistent with
+    this project or the open source license(s) involved.

LICENSE

@@ -0,0 +1,19 @@
+Copyright (c) 2021 Steven Kriegler
+
+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

@@ -58,3 +58,15 @@ Luckily, both endpoints have a proper REST API to communicate with each others.
 
 - Add user with necessary permissions
 - Create webhook on a project/organization pointing to the bot url (secure it with webhook secret)
+
+## Contributing
+
+Expected workflow is: Fork -> Patch -> Push -> Pull Request
+
+NOTES:
+
+- **Please read and follow the [CONTRIBUTORS GUIDE](CONTRIBUTING.md).**
+
+## License
+
+This project is licensed under the MIT License. See the [LICENSE](LICENSE) file for the full license text.