Set IG-88's gender to n/a; fix documentation for gender field

phalt#127

Author: erlendr

resources/fixtures/people.json

@@ -361,7 +361,7 @@
         "edited": "2014-12-20T21:17:50.351Z",
         "name": "IG-88",
         "created": "2014-12-15T12:51:10.076Z",
-        "gender": "none",
+        "gender": "n/a",
         "skin_color": "metal",
         "hair_color": "none",
         "height": "200",

swapi/templates/docs.md

@@ -201,7 +201,7 @@ A People resource is an individual person or character within the Star Wars univ
 - ```eye_color``` *string*
 -- The eye color of this person. Will be "unknown" if not known or "n/a" if the person does not have an eye.
 - ```gender``` *string*
--- The gender of this person. Either "Male", "Female" or "unknown", "n/a" if the person does not have a gender.
+-- The gender of this person. Either "male", "female" or "hermaphrodite". Will be "unknown" if not known or "n/a" if the person does not have a gender.
 - ```hair_color``` *string*
 -- The hair color of this person. Will be "unknown" if not known or "n/a" if the person does not have hair.
 - ```height``` *string*