Update README.md

You could also add comparision to [python-lolcat](https://pypi.python.org/pypi/lolcat):

```bash
$ dmesg > foo
$ time python-lolcat foo
real	0m1.503s
user	0m1.609s
sys	0m0.012s
$ time c-lolcat foo
real	0m0.055s
user	0m0.051s
sys	0m0.000s
```

1 files changed, 10 insertions, 0 deletions

diff --git a/README.md b/README.md
index 1166db1..1213a91 100644
--- a/README.md
+++ b/README.md
@@ -10,6 +10,16 @@
 
 ## Installation
 
+### Archlinux
+
+There's an [AUR package](https://aur.archlinux.org/packages/c-lolcat):
+
+```bash
+$ yaourt -S c-lolcat
+```
+
+### Others
+
 ```bash
 $ make && sudo make install
 ```