Create a "How to Contribute" page

[shawnrhoads]

We will need to create page with instructions on how to contribute along with some guidelines recommendations for recipes.

[shawnrhoads]

For now, we decided that (subject to change):

• all recipes will be written in Markdown
• all recipes will be saved to `content/recipes/*.md'
• recipe files will follow the heuristic: content/recipes/_recipe.md
• any images associated with a recipe will follow a heuristic: content/recipes/image.jpg
• code included should be roughly 1-10 lines
• recipes should include software versions and links to software documentation when possible

[scovitz]

1. Use text file generated from all-contributors to create a page for the website
2. Add documentation on how to install and use the all-contributors feature locally