readme: Added some resources and pointers to external collections

@conscott has some really nice plugins, so we link to them :-)

Signed-off-by: Christian Decker <decker.christian@gmail.com>

README.md

@@ -12,8 +12,25 @@ Community curated plugins for c-lightning.
 | [prometheus][prometheus]          | Lightning node exporter for the prometheus timeseries server |
 | [summary][summary]                | Print a nice summary of the node status                      |
 
+
+## More Plugins from the Community
+
+ - https://github.com/conscott/c-lightning-plugins
+
+## Plugin Builder Resources
+
+ - [Description of the plugin API][plugin-docs]
+ - [C Plugin API][c-api] by @rustyrussell
+ - [Python Plugin API & RPC Client][python-api] ([PyPI][python-api-pypi]) by @cdecker
+ - [Go Plugin API & RPC Client][go-api] by @niftynei
+
 [pers-chans]: https://github.com/lightningd/plugins/tree/master/persistent-channels
 [probe]: https://github.com/lightningd/plugins/tree/master/probe
 [prometheus]: https://github.com/lightningd/plugins/tree/master/prometheus
 [summary]: https://github.com/lightningd/plugins/tree/master/summary
 [donations]: https://github.com/lightningd/plugins/tree/master/donations
+[plugin-docs]: https://lightning.readthedocs.io/PLUGINS.html
+[c-api]: https://github.com/ElementsProject/lightning/blob/master/plugins/libplugin.h
+[python-api]: https://github.com/ElementsProject/lightning/tree/master/contrib/pylightning
+[python-api-pypi]: https://pypi.org/project/pylightning/
+[go-api]: https://github.com/niftynei/glightning