Reaction class

[IsaacPacht]

1. Field can be final
2. What if the input string doesn't match either "like" or "dislike"?
3. Is there any reason we have to allow for upper and lower case? Do we know which one, in practice, the code will be called with?

DashboardProject/Reaction.java

Line 4 in e78220c

private String reaction;

[fine-code]

changed Reaction.java to an enum class