Installed Stripe

I installed the Stripe gem and added an initializer for it.
Added #price Method to Keyword

I added a method to the Keyword class for calculating the price of a
message on that Keyword
Changed Methods on Message Model

I made the #send! method private, added a public #pay and #approve!
method and added a private #charge_card method all to the Message model.
Moved Validation Tests into Describe Blocks
Set Messages to Set Their Price on Create

I added a before action to the message model so it can set its price
upon create using the #price method on the Keyword model.
Added POST pay to the Message Controller

I added an action to the Message controller for paying for messages.
Added Necessary Localizations
Added a Pay Route
Corrected the Method Called on Moderate Message
Created a Pay Form
Added Price and Stripe Token to the Message Table
Merge branch 'stripe' into development