add README

Author: silloi

README.md

@@ -0,0 +1,25 @@
+## How to use
+
+### show thread
+
+```sh
+./gchan.sh show "thread name"
+```
+
+### create thread
+
+```sh
+./gchan.sh create "thread name"
+```
+
+### post message to thread
+
+```sh
+./gchan.sh post "thread name" "message"
+```
+
+### response thread
+
+```sh
+./gchan.sh response "message"
+```

main.dat

@@ -2,3 +2,4 @@ silloi<><>Mon Dec 12 18:33:44 2022 +0900<>1<>
 silloi<><>Mon Dec 12 18:33:47 2022 +0900<>2<>
 silloi<><>Mon Dec 12 22:36:35 2022 +0900<>fix for update_last_dat<>
 silloi<><>Tue Dec 13 15:09:58 2022 +0900<>update logic<>
+silloi<><>Thu Dec 15 20:55:44 2022 +0900<>fix reference error<>