Suggestion: Option for `exact: true` (or `right_wildcard: false`)

[DannyBen]

Hi,

I have noticed that exact search was somewhat discussed in #23, but I think this issue is different.

I know there is the option to disable left wildcard, but:

• I did not find an option to disable right wildcard, or even better;
• I was hoping to have an option that is called exact, that disables both left and right wildcards.

search_scope :search do
  attributes :first_name, :last_name, :location
  # was hoping for this:
  options :location, exact: true
  # or at least this:
  options :location, left_wildcard: false, right_wildcard: false
end

[mrkamel]

available in master now