Rename tag into tags

Author: polldo

designs/0002-tags.md

@@ -22,28 +22,26 @@ These commands can be:
 
 **list commands**:
 
-`thing list --tag <key0>=<value0>,<key1>=<value1>` to list all the things having all the tags passed
+`thing list --tags <key0>=<value0>,<key1>=<value1>` to list all the things having all the tags passed
 
-`device list --tag <key0>=<value0>,<key1>=<value1>` to list all the devices having all the tags passed
-
-alternative: `--filter` instead of `--tag`
+`device list --tags <key0>=<value0>,<key1>=<value1>` to list all the devices having all the tags passed
 
 
 **delete commands**:
 
-`thing delete --tag <key0>=<value0>,<key1>=<value1>` to delete all the things having all the tags passed
+`thing delete --tags <key0>=<value0>,<key1>=<value1>` to delete all the things having all the tags passed
 
-`device delete --tag <key0>=<value0>,<key1>=<value1>` to delete all the devices having all the tags passed
+`device delete --tags <key0>=<value0>,<key1>=<value1>` to delete all the devices having all the tags passed
 
 
 **ota command**:
 
-`ota upload --device-tag <key0>=<value0>,<key1>=<value1> --file <sketch-file.ino.bin>` to perform an upload via ota to all the devices having all the tags passed
+`ota upload --device-tags <key0>=<value0>,<key1>=<value1> --file <sketch-file.ino.bin>` to perform an upload via ota to all the devices having all the tags passed
 
 
 To be decided, **which flag is mandatory and which is optional**:
 In delete and ota commands, the `--id` flag should become **optional** instead of mandatory. 
-Then, if neither `--id` nor `--tag` is passed, the command could return an error telling the user to specify at least one of the two flags.
+Then, if neither `--id` nor `--tags` is passed, the command could return an error telling the user to specify at least one of the two flags.
 On the other hand, if both flags are passed, we could follow different approaches: return an error, use only one flag (only tags or only id), try to use both flags.
 
 Another thing to be decided is **how to handle errors**: