Extension samples and templates article

Signed-off-by: Shwetank Dixit <emailshwetank@gmail.com>
Sidebar change to reflect extension template article

Signed-off-by: Shwetank Dixit <emailshwetank@gmail.com>
Another fix

Signed-off-by: Shwetank Dixit <emailshwetank@gmail.com>
Merge pull request #49 from shwetank/master

Extension samples and templates article