Update README file

Add installation instructions, dependencies, authors, etc

Signed-off-by: Vicent Marti <tanoku@gmail.com>

README.md

@@ -1,4 +1,50 @@
 pygit2 - libgit2 bindings in Python
 =====================================
 
-pygit2 is a set of Python bindings to the libgit2 linkable C Git library.
+pygit2 is a set of Python 2.6+ bindings to the libgit2 linkable C Git library.
+
+INSTALLING AND RUNNING
+========================
+
+First you need to install libgit2:
+
+    $ git clone git://github.com/libgit2/libgit2.git
+    $ cd libgit2
+    $ make
+    $ make install
+
+Next, make sure you have the required library dependencies for pygit2: OpenSSL and ZLib.
+For instance, in Debian-based systems run:
+
+    $ sudo apt-get install zlib1g-dev libssl-dev
+
+Also, make sure you have Python 2.6+ installed together with the Python development headers.
+
+When those are installed, you can install pygit2:
+
+    $ git clone git@github.com:libgit2/pygit2.git
+    $ cd pygit2
+    $ python setup.py install
+    $ python setup.py test
+
+
+CONTRIBUTING
+==============
+
+Fork libgit2/pygit2 on GitHub, make it awesomer (preferably in a branch named
+for the topic), send a pull request.
+
+
+AUTHORS 
+==============
+
+* David Borowitz <dborowitz@google.com>
+
+LICENSE
+==============
+
+GPLv2 with linking exception. See COPYING for more details.
+
+
+
+