Add contribution guidelines

[ci skip]

CONTRIBUTING.md

@@ -0,0 +1,48 @@
+# Contributing to Figaro
+
+Figaro is open source and contributions from the community are encouraged! No
+ contribution is too small.
+
+Please consider:
+
+* Adding a feature
+* Squashing a bug
+* Writing documentation
+* Fixing a typo
+* Correcting [style](https://github.com/styleguide/ruby)
+
+## How do I contribute?
+
+For the best chance of having your changes merged, please:
+
+1. [Fork](https://github.com/laserlemon/figaro/fork) the project.
+2. [Write](http://en.wikipedia.org/wiki/Test-driven_development) a failing test.
+3. [Commit](http://tbaggery.com/2008/04/19/a-note-about-git-commit-messages.html) changes that fix the tests.
+4. [Submit](https://github.com/laserlemon/figaro/pulls) a pull request with *at least* one animated GIF.
+5. Be patient.
+
+If your proposed changes only affect documentation, include the following on a
+new line in each of your commit messages:
+
+```
+[ci skip]
+```
+
+This will signal [Travis](https://travis-ci.org) that running the test suite is
+not necessary for these changes.
+
+## Bug Reports
+
+If you are experiencing unexpected behavior and, after having read Figaro's
+documentation, are convinced this behavior is a bug, please:
+
+1. [Search](https://github.com/laserlemon/figaro/issues) existing issues.
+2. Collect enough information to reproduce the issue:
+  * Figaro version
+  * Ruby version
+  * Rails version
+  * Specific setup conditions
+  * Description of expected behavior
+  * Description of actual behavior
+3. [Submit](https://github.com/laserlemon/figaro/issues/new) an issue.
+4. Be patient.

README.md

@@ -234,4 +234,4 @@ My name is Steve Richert and I wrote Figaro in March, 2012 with overwhelming enc
 
 Figaro is open source and contributions from the community are encouraged! No contribution is too small.
 
-See Figaro's [contribution guidelines](#contributing) for more information.
+See Figaro's [contribution guidelines](CONTRIBUTING.md) for more information.