fixed docs for black-scholes

Author: alexandrebrilhante

docs/src/getting_started.md

@@ -10,13 +10,13 @@
 
 ## Usage
 
-To price an American option, simply create a new `AmericanOption` and pass it to `evaluate` with the desired valuation model:
+To price an European option, simply create a new `EuropeanOption` and pass it to `evaluate` with the desired valuation model:
 
 ```julia
 julia> using FinancialDerivatives
 
-julia> american_put = AmericanOption(100.0, 90.0, 0.05, 0.3, 180/365, -1)
+julia> euro_put = EuropeanOption(100.0, 90.0, 0.05, 0.3, 180/365, -1)
 
-julia> evaluate(american_put, BlackScholes())
+julia> evaluate(euro_put, BlackScholes())
 3.2281936525908073
 ```