Improve Readme

Author: danpalmer

README.md

@@ -2,9 +2,19 @@
 
 DLQ is a lightweight & modular queue and cron system for Django.
 
+## Installation
+
+```shell
+pip install django-lightweight-queue[redis]
+```
+
+Currently the only production-ready backends are redis-based, so the `redis`
+extra is essentially required. Additional non-redis backed production-ready
+backends are great candidates for community contributions.
+
 ## Basic Usage
 
-``` python
+```python
 import time
 from django_lightweight_queue import task
 
@@ -25,42 +35,50 @@ for more details.
 All automatically picked up configuration options begin with `LIGHTWEIGHT_QUEUE_`
 and can be found in `app_settings.py`. They should be placed in the usual Django
 settings files, for example:
-``` python
+
+```python
 LIGHTWEIGHT_QUEUE_BACKEND = 'django_lightweight_queue.backends.redis.RedisBackend'
 ```
 
-If desired, specific configuration overrides can be placed in a standalone python
-file which passed on the command line.
+#### Special Configuration
+
+If desired, specific configuration overrides can be placed in a standalone
+python file which passed on the command line. This is useful for applying
+customisations for specific servers.
 
 For example, given a `special.py` containing:
-``` python
+
+```python
 LIGHTWEIGHT_QUEUE_REDIS_PORT = 12345
 ```
+
 and then running:
+
 ```
 $ python manage.py queue_runner --config=special.py
 ```
+
 will result in the runner to use the settings from the specified configuration
 file in preference to settings from the Django environment. Any settings not
 present in the specified file are inherited from the global configuration.
 
 ### Backends
 
 There are four built-in backends:
-- Synchronous (the default): executes the task inline, without any actual queuing
-- Redis: executes tasks at-most-once using [Redis][redis] for storage of the
-  enqueued tasks
-- Reliable Redis: executes tasks at-least-once using [Redis][redis] for storage
-  of the enqueued tasks
-- Debug Web: a backend for use in debugging. Instead of running jobs it prints
-  the url to a view that can be used to run a task in a transaction which will
-  be rolled back. This is useful for debugging and optimising tasks.
+
+| Backend        | Type        | Description                                                                                                                                                                       |
+| -------------- | ----------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
+| Synchronous    | Development | Executes the task inline, without any actual queuing.                                                                                                                             |
+| Redis          | Production  | Executes tasks at-most-once using [Redis][redis] for storage of the enqueued tasks.                                                                                               |
+| Reliable Redis | Production  | Executes tasks at-least-once using [Redis][redis] for storage of the enqueued tasks (subject to Redis consistency). Does not guarantee the task _completes_.                      |
+| Debug Web      | Debugging   | Instead of running jobs it prints the url to a view that can be used to run a task in a transaction which will be rolled back. This is useful for debugging and optimising tasks. |
 
 [redis]: https://redis.io/
 
 ## Running Workers
 
 The queue runner is implemented as a Django management command:
+
 ```
 $ python manage.py queue_runner
 ```
@@ -73,37 +91,47 @@ $ python manage.py queue_runner --machine 2 --of 4
 ```
 
 Alternatively a runner can be told explicitly which configuration to use:
+
 ```
 $ python manage.py queue_runner --exact-configuration --config=special.py
 ```
+
 When using `--exact-configuration` the number of workers is configured exactly,
 rather than being treated as the configuration for a pool. Additionally,
 exactly-configured runners will _not_ run any cron workers.
 
 ### Example
 
 Given a Django configuration containing:
-``` python
+
+```python
 LIGHTWEIGHT_QUEUE_WORKERS = {
     'queue1': 3,
 }
 ```
+
 and a `special.py` containing:
-``` python
+
+```python
 LIGHTWEIGHT_QUEUE_WORKERS = {
     'queue1': 2,
 }
 ```
+
 Running any of:
+
 ```
 $ python manage.py queue_runner --machine 1 --of 3 # or,
 $ python manage.py queue_runner --machine 2 --of 3 # or,
 $ python manage.py queue_runner --machine 3 --of 3
 ```
+
 will result in one worker for `queue1` on the current machine, while:
+
 ```
 $ python manage.py queue_runner --exact-configuration --config=special.py
 ```
+
 will result in two workers on the current machine.
 
 ## Cron Tasks
@@ -115,7 +143,7 @@ To specify that a management command should be run at a given time, place a
 `cron.py` file in the root folder of the Django app which defines the command
 and which contains a `CONFIG` variable:
 
-``` python
+```python
 CONFIG = (
     {
         'command': 'my_cron_command',