(chore)Update Contributing section (#166)

* (chore) Update Contributing section

Update "Contributing" section in the README and wiki page.

Specify we are looking to improve test coverage and Code Climate score.

* (chore) add links to codeclimate

* (chore) rephrase readme section

* (chore) fix typo in the readme

Author: elfrank

README.md

@@ -4,7 +4,7 @@
 # Ray Tracing Renderer
 A [Three.js](https://github.com/mrdoob/three.js/) renderer which utilizes path tracing to render a scene with true photorealism. The renderer supports global illumination, reflections, soft shadows, and realistic environment lighting.
 
-[Demo](https://hoverinc.github.io/ray-tracing-renderer/scenes/sample-models/) | [User Guide](https://github.com/hoverinc/ray-tracing-renderer/wiki/User-Guide) | [API Reference](https://github.com/hoverinc/ray-tracing-renderer/wiki/RayTracingRenderer) | [Contributing](https://github.com/hoverinc/ray-tracing-renderer/wiki/Contributing)
+[Demo](https://hoverinc.github.io/ray-tracing-renderer/scenes/sample-models/) | [User Guide](https://github.com/hoverinc/ray-tracing-renderer/wiki/User-Guide) | [API Reference](https://github.com/hoverinc/ray-tracing-renderer/wiki/RayTracingRenderer) | [Contributing](https://github.com/hoverinc/ray-tracing-renderer#contributing)
 
 
 ## Usage
@@ -64,6 +64,15 @@ Ray Tracing Renderer runs on WebGL2, and does so by implementing a [path tracing
 * **Progressive rendering.** Path tracing is a progressive method. This means that the more computation time that is spent on rendering, the better the resulting image looks. In order to render a high quality image, the camera must stay still for several seconds, as the render gradually improves. This is in stark contract to WebGLRenderer's method which is able to render a full quality image in one frame.
 * **Static geometry**. A BVH acceleration structure is computed for the scene to speed up ray intersections. This computation can take several seconds when first initializing the renderer, and it must be recomputed whenever scene geometry moves or changes. Therefore only camera movement is supported in real-time.
 
-We are currently developing solutions to both these limitations, so that a full, noise-free render can be rendered in just one frame, as well as being able to support dynamic geometry.
-
 For a more detailed guide on how to use the renderer, please read the [User Guide](https://github.com/hoverinc/ray-tracing-renderer/wiki/User-Guide) .
+
+## Contributing
+We want to increase test coverage and maintanability of the repo. If you would like to contribute, take a look at the following and submit Pull Requests:
+* [CodeClimate issues](https://codeclimate.com/github/hoverinc/ray-tracing-renderer/issues) to improve maintainability, and
+* Unit tests to [improve our coverage](https://codeclimate.com/github/hoverinc/ray-tracing-renderer/code)
+
+Take a look to [this page](https://github.com/hoverinc/ray-tracing-renderer/wiki/Submitting-Changes) with more details about submitting changes to the project.
+
+### Expectations
+
+This repository started as a side-project and the time we invest on it is limited. It may take us a few days to get back to you but please bring your ideas forward. We'll do our best to respond promptly.