doc: ut3 authentication

README.md

@@ -12,7 +12,7 @@ This project tries to make CELCAT usable by:
 
 ### Usage
 ```
-Usage: fetch-celcat [OPTIONS] COURSE_REQUEST_FILE
+Usage: fetch-celcat [OPTIONS] COURSE_REQUEST_FILE CREDENTIALS_FILE
 
 Options:
   --json, --json-raw TEXT  If set, raw CELCAT events are written as JSON to this file.
@@ -23,7 +23,7 @@ Options:
   --help                   Show this message and exit.
 ```
 
-The course request input file defines which courses you are interested in.
+**The course request input file** defines which courses you are interested in.
 For example, if you give the following courses:
 
 - BAS (apogee code KINXIB11)
@@ -41,6 +41,15 @@ KINXIB11,BAS,2022-09-05 00:00:00,2022-10-21 23:59:00,TP,INXIB11A42,3
 KINXIB21,SR1,2022-09-05 00:00:00,2022-10-21 23:59:00,TP,INXIB21A42,5
 ```
 
+**The credentials input file** is a JSON file that contains your UT3 credential information, for example:
+
+```json
+{
+    "username": "YOUR_UT3_USERNAME",
+    "password": "YOUR_UT3_PASSWORD"
+}
+```
+
 ### Use this script with caution
 The only life jacket of this script is that it prints a warning if the number of fetched events is not the expected one for each course request.