Make URL:s clickable inside the description

Belongs to #39 -  Uses rails_autolink. Makes URLs clickable and opens new web page. Email addresses open default email app.
 Changes to be committed:
Merge pull request #36 from akesulah/development

Modify Idea index view

resolves #33
'New Idea' to the Navigation Bar & redirect to Idea

Added New Idea button to the navbar and after creating a new idea user can see the created idea (redirect_to @idea).
Merge pull request #40 from satukark/development

Make URLs clickable inside the description

resolves #39
Add dropbox for keywords on left sidebar
Add the keyword that was selected from the dropbox to the idea in question
Add checkmark to the keywords in dropbox that are already attached to idea and prevent adding a keyword twice
Update README.md
Add dropbox to sidebar where a Keyword can be added to an Idea

Keyword cannot be added if the Idea already has it. Test was modified to test only the keyword present in the list not in the dropbox. Does not have issue yet and does not resolve the task.
Merge branch 'dropdown' into development

Add dropbox to ideas/1 page from where a new keyword can be added to the Idea
Add dropbox from where a Keyword can be attached to an Idea

Keyword cannot be added if Idea already has it.
Merge pull request #43 from hwikgren/development

Add dropbox from where a Keyword can be added to an Idea
Update README.md
Merge pull request #42 from satukark/patch-1

Update README.md