Document the directory structure

README.md

@@ -126,4 +126,4 @@ You may want to inspect `<my_dir>/gfx/Cargo.toml` for other modules typically us
 ## Note
 
 gfx is still in development. API may change with new backends/features to be implemented.
-If you are interested in helping out, please contact the developers on [Gitter](https://gitter.im/gfx-rs/gfx).
+If you are interested in helping out, checkout [contrib.md](info/contrib.md) and do not hesitate to contact the developers on [Gitter](https://gitter.im/gfx-rs/gfx).

info/contrib.md

@@ -26,13 +26,16 @@ There is also a [Waffle board](https://waffle.io/gfx-rs/gfx-rs), which you can u
 
 Finally, feel free to hop on [#rust-gamedev](http://chat.mibbit.com/?server=irc.mozilla.org&channel=%23rust-gamedev).
 
-### Issues
-
-Labels are formatted as "M-render", where "M" is a category among those:
-  * **T** = Type: *bug*, *discussion*, *doc*, *feature*, *optimization*, *refactor*
-  * **S** = Status: *blocked*, *duplicate*, *invalid*, *ready*, *working*
-  * **D** = Difficulty: *easy*, *hard*, *medium*
-  * **M** = Module: *device*, *user*, *render*, *structure*
+### Directory Structure 
+
+* _examples_ : GFX's examples
+* _tests_ : GFX's tests
+* _info_ : Information and documentation
+* _src_ : gfx_app, an application framework for GFX
+* _src/core_ : gfx_core, core structures and the interface that backends must provide
+* _src/backend_ : The backends implementations
+* _src/render_ : The main gfx package
+* _src/window_ : Different backends to create windows and initialize their graphics
 
 ### Code