Added contributing documentation

This lowers the barrier to entry on contributing to AASM by providing a
more detailed guide on how to get the project installed for local
development.

CONTRIBUTING.md

@@ -0,0 +1,24 @@
+## Contributing ##
+
+While not required to contribute, we recommend [RVM](https://rvm.io/) to manage your rubies.
+
+1. Read the [Contributor Code of Conduct](https://github.com/aasm/aasm/blob/master/CODE_OF_CONDUCT.md)
+2. [Fork it](https://help.github.com/articles/about-forks/)
+3. Clone the project `git clone git@github.com:[YOUR GITHUB USERNAME]/aasm.git`
+4. `cd aasm`
+5. Create your feature branch `git checkout -b my-new-feature`
+6. Write tests for your changes (feature/bug)
+7. Write your (feature/bugfix)
+8. Install the dependencies `appraisal install`
+9. Run the tests `appraisal rspec`
+10. Commit your changes `git commit -am 'Added some feature'`
+11. Push to the branch `git push origin my-new-feature`
+12. Create new [Pull Request](https://help.github.com/articles/creating-a-pull-request/)
+
+There are some option dependencies as well.
+
+- [MongoDB server](https://www.mongodb.com/download-center)
+- [Redis](https://redis.io/topics/quickstart)
+- [DynamoDB (local)](https://docs.aws.amazon.com/amazondynamodb/latest/developerguide/DynamoDBLocal.html)
+
+If we've missed something please open an [issue](https://github.com/aasm/aasm/issues/new)

README.md

@@ -1086,14 +1086,7 @@ Feel free to
 * [Anil Maurya](http://github.com/anilmaurya) (since 2016)
 
 
-## Contributing ##
-
-1. Read the [Contributor Code of Conduct](https://github.com/aasm/aasm/blob/master/CODE_OF_CONDUCT.md)
-2. Fork it
-3. Create your feature branch (git checkout -b my-new-feature)
-4. Commit your changes (git commit -am 'Added some feature')
-5. Push to the branch (git push origin my-new-feature)
-6. Create new Pull Request
+[## Contributing ##](contributing.md)
 
 ## Warranty ##