Added installation docs

docs/installation.rst

@@ -3,4 +3,101 @@
 Installation
 ============
 
-Blafasel, add me
+Flask is a microframework and yet it depends on external libraries.  There
+are various ways how you can install that library and this explains each
+way and why there are multiple ways.
+
+Flask depends on two external libraries: `Werkzeug
+<http://werkzeug.pocoo.org/>`_ and `Jinja2 <http://jinja.pocoo.org/2/>`_.
+The first on is responsible for interfacing WSGI the latter to render
+templates.  Now you are maybe asking, what is WSGI?  WSGI is a standard
+in Python that is basically responsible for ensuring that your application
+is behaving in a specific way that you can run it on different
+environments (for example on a local development server, on an Apache2, on
+lighttpd, on Google's appengine or whatever you have in mind).
+
+So how do you get all that on your computer in no time?  The most kick-ass
+method is virtualenv, so let's look at that first.
+
+virtualenv
+----------
+
+Virtualenv is what you want to use during development and in production if
+you have shell access.  So first: what does virtualenv do?  If you are
+like me and you like Python, chances are you want to use it for another
+project as well.  Now the more projects you have, the more likely it is
+that you will be working with different versions of Python itself or a
+library involved.  Because let's face it: quite often libraries break
+backwards compatibility and it's unlikely that your application will
+not have any dependencies, that just won't happen.  So virtualenv for the
+rescue!
+
+It basically makes it possible to have multiple side-by-side
+"installations" of Python, each for your own project.  It's not actually
+an installation but a clever way to keep things separated.
+
+So let's see how that works!
+
+If you are on OS X or Linux chances are that one of the following two
+commands will for for you::
+
+    sudo easy_install virtualenv
+
+or even better::
+
+    sudo pip install virtualenv
+
+Changes are you have virtualenv installed on your system then.  Maybe it's
+even in your package manager (on ubuntu try ``sudo apt-get install
+python-virtualenv``).
+
+On windows, just installed virtualenv from the `Python Package Index
+<http://pypi.python.org/pypi/virtualenv>`_.
+
+So now that you have virtualenv running just fire up a shell and create
+your own environment.  I usually create a folder and a `env` folder
+within::
+
+    $ mkdir myproject
+    $ cd myproject
+    $ virtualenv env
+    New python executable in env/bin/python
+    Installing setuptools............done.
+
+Now you only have to activate it, whenever you work with it.  On OS X and
+Linux do the following::
+
+    $ source env/bin/activate
+
+If you are a Windows user, the following command is for you::
+
+    $ env\scripts\activate
+
+Either way, you should now be using your virtualenv (see how the prompt of
+your shell has changed to show the virtualenv).
+
+Now you can just enter the following command to get Flask activated in
+your virtualenv::
+
+    $ easy_install Flask
+
+A few seconds later you are good to go.
+
+
+System Wide Installation
+------------------------
+
+This is possible as well, but I would not recommend it.  Just run
+`easy_install` with root rights::
+
+    sudo easy_install Flask
+
+(Run it in an Admin shell on Windows systems and without the `sudo`). 
+
+
+The Drop into Place Version
+---------------------------
+
+Now I really don't recommend this way on using Flask, but you can do that
+of course as well.  Download the `dip` zipfile from the website and unzip
+it next to your application.