new models and views added.

Didn`t get time to go through the tutorial. Just did the change with my
understanding based on ur code. without test.  I`m also not very clear
with how the url works with AJAX call. So left it there. Seems Django
couldn`t handle multi-primary key so changed the data model a little
bit. Don`t need to worry about the Training Plans since we don`t have a
clear requirement. Later we need to modify this section anyways.