Add CONTRIBUTING.md + update contribution and development steps

CONTRIBUTING.md

@@ -0,0 +1,38 @@
+# Contributing
+
+## To contribute:
+
+[Kill some bugs :)](https://github.com/daviferreira/medium-editor/issues?q=is%3Aopen+is%3Aissue+label%3Abug)
+
+1. Fork it
+2. Create your feature branch (`git checkout -b my-new-feature`)
+3. Test your changes to the best of your ability.
+4. Update the documentation to reflect your changes if they add or changes current functionality.
+5. Commit your changes (`git commit -am 'Added some feature'`)
+6. Push to the branch (`git push origin my-new-feature`)
+7. Create new Pull Request
+
+Looking for something simple for a first contribution? Try fixing an [easy first bug](https://github.com/daviferreira/medium-editor/issues?q=is%3Aopen+is%3Aissue+label%3A%22easy+first+bug%22)!
+
+## Development
+
+MediumEditor development tasks are managed by Grunt. To install all the necessary packages, just invoke:
+
+```bash
+npm install
+```
+
+To run all the test and build the dist files for testing on demo pages, just invoke:
+```bash
+grunt
+```
+
+These are the other available grunt tasks:
+
+* __js__: runs jslint and jasmine tests and creates minified and concatenated versions of the script;
+* __css__: runs autoprefixer and csslint
+* __test__: runs jasmine tests, jslint and csslint
+* __watch__: watch for modifications on script/scss files
+* __spec__: runs a task against a specified file
+
+The source files are located inside the __src__ directory.  Be sure to make changes to these files and not files in the dist directory.

README.md

@@ -232,14 +232,20 @@ MediumEditor development tasks are managed by Grunt. To install all the necessar
 npm install
 ```
 
-These are the available grunt tasks:
+To run all the test and build the dist files for testing on demo pages, just invoke:
+```bash
+grunt
+```
+
+These are the other available grunt tasks:
 
 * __js__: runs jslint and jasmine tests and creates minified and concatenated versions of the script;
 * __css__: runs autoprefixer and csslint
 * __test__: runs jasmine tests, jslint and csslint
 * __watch__: watch for modifications on script/scss files
+* __spec__: runs a task against a specified file
 
-The source files are located inside the __src__ directory.
+The source files are located inside the __src__ directory.  Be sure to make changes to these files and not files in the dist directory.
 
 ## Contributing
 
@@ -253,6 +259,8 @@ The source files are located inside the __src__ directory.
 6. Push to the branch (`git push origin my-new-feature`)
 7. Create new Pull Request
 
+Looking for something simple for a first contribution? Try fixing an [easy first bug](https://github.com/daviferreira/medium-editor/issues?q=is%3Aopen+is%3Aissue+label%3A%22easy+first+bug%22)!
+
 ## Contributors
 
 [https://github.com/daviferreira/medium-editor/graphs/contributors](https://github.com/daviferreira/medium-editor/graphs/contributors)