docs: Add READMEs

Signed-off-by: Julien Riou <julien@riou.xyz>

README.md

@@ -1,3 +1,53 @@
 # Coller
 
-Simple self-contained pastebin solution.
+Simple self-contained pastebin solution written in Go.
+
+# Description
+
+Coller is a set a binaries:
+- **collerd**: HTTP server to handle note management
+- **coller**: CLI to create notes
+- **copier**: CLI to download and decrypt notes (client-side decryption)
+
+# Installation
+
+## From source code
+
+Requires [Go](https://go.dev/dl/).
+
+```
+git clone https://git.riou.xyz/jriou/coller.git
+cd coller
+make
+sudo cp -p bin/* /usr/local/bin/
+```
+
+## Docker
+
+```
+git clone https://git.riou.xyz/jriou/coller.git
+cd coller
+docker build -t coller:latest .
+docker run --network host --rm --name collerd -p 8080:8080 coller:latest
+```
+
+Then go to http://localhost:8080 (website).
+
+## Ansible
+
+See [ansible-role-coller](https://git.riou.xyz/jriou/ansible-role-coller).
+
+
+# Usage and configuration
+
+* [collerd](src/cmd/collerd/README.md)
+* [coller](src/cmd/coller/README.md)
+* [copier](src/cmd/copier/README.md)
+
+# Contributions
+
+Contributions are welcomed! Feel free to provide unit tests when possible. Lint your code with `go fmt`. If you don't feel confident enough to contribute, feel free to open an issue to describe the feature you would like to see implemented or the problem you are facing.
+
+# License
+
+See [LICENSE](LICENSE).