Building Ruby 1.9.2 and installing rails 3.0 on it -- On Ubuntu 10.04 - Lucid Lynx

Issues that I faced while building Ruby 1.9.2 and then installing Rails 3.0 and finally making the example in "Getting started with Rails guide".

Make sure the following development libraries are installed before you start building ruby:
(The ruby configure, make and make install (i.e. building and installing) will not tell you anything about these missing libraries)

1) zlib-dev (I think the package name is zlib1g-dev) -- Needed when you try to install the rails gem. If this is not available you will get the following error when you try to install rails with the command :

gem install rails

ERROR: Loading command: install (LoadError) no such file to load -- zlib

2) libssl-dev -- Needed when you try to run the inbuilt rails WEBrick server and load the first example app in the getting started guide. You will get an error of the type:

"LoadError: no such file to load -- openssl"

In my case I did not have this library the first time I built ruby. So I followed the instructions given here to build the openssl-ruby module/binding.
After this I ran `make` and `make install` from the top ruby source directory. May be that was not necessary, but I did it anyways.

Also, I am guessing that if this package was available when I first built ruby then the openssl-ruby module would be built by default. If not there should be a configure option to enable this `feature`. The configure's help output does not provide any info on this (not even the --help=recursive option).

==== Upgrading from older ruby versions ====

Older ruby versions used the folder /usr/local/lib/ruby/site_ruby//rubygems . Now apparently this directory is replaced by /usr/local/lib/ruby//rubygems .

So you will have to get rid of the site_ruby folder (i.e. delete it) so that the gems are not searched for and used from a stale folder.

Not doing this might result in you not being able to run gem at all.