Using correct serialize method

Author: pengrad

library/src/main/java/com/pengrad/telegrambot/request/BaseRequest.java

@@ -13,7 +13,7 @@
  */
 abstract public class BaseRequest<T extends BaseRequest, R extends BaseResponse> {
 
-    protected static final Gson gson = new Gson();
+    private static final Gson gson = new Gson();
 
     @SuppressWarnings("unchecked")
     protected final T thisAsT = (T) this;

library/src/main/java/com/pengrad/telegrambot/request/RestrictChatMember.java

@@ -16,7 +16,7 @@ public RestrictChatMember(Object chatId, int userId) {
 
     public RestrictChatMember(Object chatId, int userId, ChatPermissions permissions) {
         super(BaseResponse.class);
-        add("chat_id", chatId).add("user_id", userId).add("permissions", gson.toJson(permissions));
+        add("chat_id", chatId).add("user_id", userId).add("permissions", serialize(permissions));
     }
 
     public RestrictChatMember untilDate(int untilDate) {

library/src/main/java/com/pengrad/telegrambot/request/SetChatPermissions.java

@@ -11,6 +11,6 @@ public class SetChatPermissions extends BaseRequest<SetChatPermissions, BaseResp
 
     public SetChatPermissions(Object chatId, ChatPermissions permissions) {
         super(BaseResponse.class);
-        add("chat_id", chatId).add("permissions", gson.toJson(permissions));
+        add("chat_id", chatId).add("permissions", serialize(permissions));
     }
 }