Load providers by class & module name. Closes #6

README.md

@@ -15,3 +15,19 @@ Currently supports:
 * Parks n Peaks
 * RBN
 * APRS
+
+### Writing your own Providers
+
+(S)pothole is designed to be easily extensible. If you want to write your own provider, simply add a module to the `providers` package containing your class. (Currently, in order to be loaded correctly, the module (file) name should be the same as the class name, but lower case.)
+
+Your class should extend "Provider"; if it operates by polling an HTTP Server on a timer, it can instead extend "HTTPProvider" where some of the work is done for you.
+
+The class will need to implement a constructor that takes in the `provider_config` and provides it to the superclass constructor, while also taking any other config parameters it needs.
+
+If you're extending the base `Provider` class, you will need to implement `start()` and `stop()` methods that start and stop a separate thread which handles the provider's processing needs. The thread should call `submit()` or `submit_batch()` when it has one or more spots to report.
+
+If you're extending the `HTTPProvider` class, you will need to provide a URI to query and an interval to the superclass constructor. You'll then need to implement the `http_response_to_spots()` method which is called when new data is retrieved. Your implementation should then call `submit()` or `submit_batch()` when it has one or more spots to report.
+
+When constructing spots, use the comments in the Spot class and the existing implementations as an example. All parameters are optional, but you will at least want to provide a `time` (which must be timezone-aware) and a `dx_call`.
+
+Finally, simply add the appropriate config to the `providers` section of `config.yml`, and your provider should be instantiated on startup.