add documentation

README.md

@@ -1,7 +1,115 @@
 # NUR
-Nix User Repository.
-User contributed nix packages
 
 [![Build Status](https://travis-ci.com/nix-community/NUR.svg?branch=master)](https://travis-ci.com/nix-community/NUR)
 
-This should become an index for user contributed package sets.
+The Nix User Repository (NUR) is community-driven meta repository for nix packages
+It provides access to user repositories that contain package descriptions (nix
+expressions) and allow to install those by referencing them via attributes.
+In contrast to [nixpkgs](https://github.com/NixOS/nixpkgs/) packages are build
+from source and are not reviewed by Nixpkgs member.
+The NUR was created to share new packages from the community in a faster and
+more decentralized way.
+NUR automatically check its list of repositories and perform evaluation checks
+before it propagated the update.
+
+## How to use
+
+First include NUR in your `packageOverrides`:
+
+To make NUR accessible for your login user, add the following to `~/.config/nixpkgs/config.nix`:
+
+```nix
+{
+  packageOverrides = pkgs: {
+    nur = pkgs.callPackage (import (builtins.fetchGit {
+      url = "https://github.com/nix-community/NUR";
+    })) {};
+  };
+}
+```
+
+For NixOS add the following to your `/etc/nixos/configuration.nix`:
+
+```nix
+{
+  nixpkgs.config.packageOverrides = pkgs: {
+    nur = pkgs.callPackage (import (builtins.fetchGit {
+      url = "https://github.com/nix-community/NUR";
+    })) {};
+  }
+}
+```
+
+Then packages can be used or installed from the nur namespace.
+
+```console
+$ nix-shell -p nur.repos.mic92.inxi
+nix-shell> inxi
+CPU: Dual Core Intel Core i7-5600U (-MT MCP-) speed/min/max: 3061/500/3200 MHz Kernel: 4.14.51 x86_64
+Up: 20h 55m Mem: 12628.4/15926.8 MiB (79.3%) HDD: 465.76 GiB (39.3% used) Procs: 409
+Shell: bash 4.4.23 inxi: 3.0.10
+```
+
+or
+
+```console
+$ nix-env -iA nur.repos.mic92.inxi
+```
+
+or
+
+```console
+# configuration.nix
+environment.systemPackages = [
+  nur.repos.mic92.inxi
+];
+```
+
+Each contributor can register their repository under a name and is responsible
+for its content.
+NUR does not check repository for malicious content on a regular base and it is
+recommend to check expression before installing them.
+
+
+## How to add your own repository.
+
+First create a repository that contains a `default.nix` in its top-level directory.
+
+DO NOT import packages for example `with import <nixpkgs> {};`.
+Instead take all dependency you want to import from nixpkgs by function arguments.
+Each repository should return a set of nix derivations:
+
+```
+{ callPackage }:
+{
+  inxi = callPackage ./inxi {};
+}
+```
+
+In this example `inxi` would be a directory
+
+Add your own repository to in the `repos.json` of NUR:
+
+```
+$ git clone https://github.com/nix-community/NUR
+# open and modify repos.json in an editor
+```
+
+```
+{
+    "repos": {
+        "mic92": {
+            "url": "https://github.com/Mic92/nur-packages"
+        },
+        "<fill-your-repo-name>": {
+            "url": "https://github.com/<your-user>/<your-repo>"
+        }
+    }
+}
+```
+
+At moment each URL must point to a git repository. By running `nur/update.py`
+the corresponding `repos.json.lock` is updated and the result tested. This will
+perform also an evaluation check, which must be passed. Commit the changed
+`repos.json` but NOT `repos.json.lock` and open a pull request towards
+https://github.com/nix-community/NUR.

repos.json

@@ -1,8 +1,7 @@
 {
-  "repos": {
-      "mic92": {
-          "url": "https://github.com/Mic92/nur-packages",
-          "maintainers": [ "Mic92" ]
-      }
-  }
+    "repos": {
+        "mic92": {
+            "url": "https://github.com/Mic92/nur-packages"
+        }
+    }
 }