update install docs

docs/dev/docs.dev.install.md

@@ -11,15 +11,34 @@
 
 ### ERPNext Installer (Beta)
 
-Install ERPNext in one command!
-
+1. Make sure that you have Python 2.7+
+```
+$ python -c "import platform; print platform.python_version()"
+2.7.3
+```
+or
+```
+$ which python2.7
+/usr/bin/python2.7
+```
+If your python version is less than 2.7, then follow,
+	* For CentOS, you can refer to http://toomuchdata.com/2012/06/25/how-to-install-python-2-7-3-on-centos-6-2/
+	* For Ubuntu, refer to http://askubuntu.com/questions/101591/how-do-i-install-python-2-7-2-on-ubuntu/101595#101595
+1. Make sure the 'passwd' command exists. Install passwd if necessary (e.g. on CentOS, run `yum install passwd`)
 1. Switch to root user using `sudo su`
-1. Create a folder where you want to install erpnext
-1. Go to the new folder
 1. `wget https://raw.github.com/webnotes/erpnext/master/install_erpnext.py`
-1. `python install_erpnext.py`
+1. `python2.7 install_erpnext.py --create_user`
+
+ This will create a user 'erpnext' and install erpnext in its home directory.
+To start a development server, login as erpnext with password erpnext (or `su erpnext` from your root shell)
+```
+cd /home/erpnext/erpnext
+./lib/wnf.py --serve
+```
 
 > If you are installing on your server for deployment, remember to change Administrator's password!
+> You can set the erpnext username and password by passing it to the install script,
+`python2.7 install_erpnext.py --create_user --username erpnext_username --password secretpassword`
 
 > If you get stuck, post your questions at [ERPNext Developer Forum](https://groups.google.com/forum/#!forum/erpnext-developer-forum)
 
@@ -37,5 +56,10 @@ Install ERPNext in one command!
 ### Upgrade / run latest patches
 
 1. Backup your database!
-1. Go to Setup > Update ERPNext
-1. Click on 'Update'
+```
+./lib/wnf.py --backup
+```
+1. Pull changes
+```
+./lib/wnf.py --update origin master
+```