Modifications to README.md and CONTRIBUTING.md

Author: jreniel

CONTRIBUTING.md

@@ -0,0 +1,6 @@
+# Contributing
+
+When contributing to this repository, please first discuss the change you wish to make via issue,
+email, or any other method with the owners of this repository before making a change. 
+
+Works created by U.S. Federal employees as part of their jobs typically are not eligible for copyright in the United States. In places where the contributions of U.S. Federal employees are not eligible for copyright, this work is in the public domain. In places where it is eligible for copyright, such as some foreign jurisdictions, this work is licensed as described in LICENSE.md.

README.md

@@ -60,4 +60,8 @@ hgrid.write_boundaries("/path/to/output/dir", overwrite=True)
 from pyschism.mesh import Hgrid
 hgrid = Hgrid.open('hgrid.gr3')
 hgrid.write("/path/to/output/file.2dm", fmt='2dm')
-```
+```
+---
+Questions, comments and suggestions are welcome. Please follow the instructions on the `CONTRIBUTING.md` file for contributions. For bug reports and feature requests, please open an issue using the issue tracker.
+Author contact: [email protected]
+