Implementing QnA Forum like Stackflow

Resource Used in implementing QnA Forum

1) Ruby1.9.3p0
2) Rails 3.2.2
3) SASS
4) Coffeescript
5) Devise 2.0.4
6) Bootstrap2.0 with simple form
7) humane js

Higher Overview Of Project

1) First Screen is Login Screen which forced user to either login or register itself with websites.
2) After login/Registration, User is redirected to '/questions' url, its list total number of question ask in forum in side bar and recent question with answer is shown in middle of '/questions'. 

3) Clicking on title of question in side bar of page bring that question to front page of page with answer listing.

4) Clicking on Title of question in front view of question pages , redirect user to question show page where he can fill answer.

5) on "/questions" pages, on top right side there is a link to add question, form is opened in pop up when button is clicked.On pop up form , form is submitted through ajax.

6) On "/questions/:id' show page, there is option for vote up and vote down, entering answer , all of these done through without page refreshes i.e through ajax.

7) There is also validation to check if same user does not click same answer for vote two times. Error message is shown 

8) Error message is shown on top-right side of page.

Table Used in Project

1)User
2)Question
3)Answer
4)UserRatedAnswer

Code in controller

Code for vote up and down is written in answer controller 
There is multiple partial used in answer index page as well question show page.

Assume In voting

User who has can rate his answer as well

Model spec is also included