rospy ImportError - cannot find custom module under src/ folder

edit

Here are the steps to reproduce:

1. create a new package under ~/catkin_ws/src:

   catkin_create_pkg foopy rospy
   

2. create src/foopy folder and add __init__.py in it

3. create a main.py under scripts/ folder:

#!/usr/bin/env python
# -*- coding: utf-8

import roslib; roslib.load_manifest('foopy')
import rospy

import sys
for f in sys.path:
    print f

/home/k/catkin_ws/src/foopy/scripts
/usr/local/lib/python2.7/dist-packages
/home/k/catkin_ws/devel/lib/python2.7/dist-packages
/opt/ros/indigo/lib/python2.7/dist-packages
/usr/lib/python2.7
...

Which does not include module foopy of my src/foopy folder. So when I import anything created under src/foopy/, it will raise an ImportError.

How to solve this issue?