Adds basic contributing rules

related to #46 and #47

CONTRIBUTING.md

@@ -0,0 +1,39 @@
+# Contributing to PISA
+
+The following is a set of guidelines for contributing to PISA.
+
+## Code Style Guidelines
+We use [black](https://github.com/psf/black) as our base code formatter. Before submitting a PR make sure you have properly formatted your code by running:
+
+```
+black {source_file_or_directory}
+```
+On top of that, there are a few rules to also have in mind.
+
+### Code Spacing
+Blocks of code should be created to separate logical sections
+
+```python
+responder = Responder(db_manager)
+responder.jobs, responder.tx_job_map = Builder.build_jobs(responder_jobs_data)
+
+watcher.responder = responder
+watcher.appointments, watcher.locator_uuid_map = Builder.build_appointments(watcher_appointments_data)
+```
+We favour spacing between blocks like `if/else`, `try/except`, etc.
+
+```python
+if tx in missed_confirmations:
+    missed_confirmations[tx] += 1
+
+else:
+    missed_confirmations[tx] = 1
+```
+
+## Code Documentation
+Code should be, at least, documented using docstrings. We use the [Sphinx Google Style](https://www.sphinx-doc.org/en/master/usage/extensions/example_google.html#example-google) for documenting functions.
+
+## Test Coverage
+Tests should be provided to cover both positive and negative conditions. Test should cover both the proper execution as well as all the covered error paths. PR with no proper test coverage will be rejected. 
+
+