Merge pull request #1060 from deepthivenkat/Issue#1059

Fixes #1059 - Update contributing.md to address Ubuntu specific Node.js and Virtual Environment Issues

CONTRIBUTING.md

@@ -211,6 +211,18 @@ sudo apt-get update
 sudo apt-get install python2.7 python2.7-dev
 ```
 
+In Ubuntu, sometimes even after installing Node.js, the command `node -v` does not show the installed version. To complete installation, a symbolic link has to be created to the sbin folder.
+
+```
+#remove old symbolic links if any 
+sudo rm -r /usr/bin/node
+
+#add new symbolic link
+sudo ln -s /usr/bin/nodejs /usr/bin/node
+sudo ln -s /usr/bin/nodejs /usr/sbin/node
+```
+
+
 ### Simple setup (Mac OS and Linux)
 #### Initializing Project source code
 
@@ -277,8 +289,11 @@ source env/bin/activate
 #  Linux: http://pillow.readthedocs.org/en/3.0.x/installation.html#linux-installation
 # install rest of dependencies
 pip install -r requirements.txt
+# In Ubuntu, if ImportError: No module named flask.ext.github occurs, it means the dependencies in requirements.txt are installed in /usr/lib instead of <project_repository>/env/python<version>/site-packages.
+# In this case, use virtual environment's pip from <project_repository>/env/lib/pip folder of the project repository instead of the global pip.
 ```
 
+
 #### Installing Grunt
 
 We use [Grunt](http://gruntjs.com/) as a task runner to perform certain things (minify + concat JS assets, for example). You need to have [Node.js](https://nodejs.org/en/download/) installed to be able to run Grunt. Once that's done, `npm` can be used to install Grunt and other build dependencies.