Add contributors into package.json (#67)

Author: kazuhitoyokoi

package.json

@@ -22,6 +22,24 @@
         {
             "name": "Hiroki Uchikawa"
         },
+        {
+            "name": "Yuki Naganuma"
+        },
+        {
+            "name": "Hiroshi Nasu"
+        },
+        {
+            "name": "Jana Backhus"
+        },
+        {
+            "name": "Kunihiko Toumura"
+        },
+        {
+            "name": "Yu Nakata"
+        },
+        {
+            "name": "Yuma Matsuura"
+        },
         {
             "name": "Qi Xiu"
         },