How to install self-developed plugins

I find a kong-plugins , named mirror and i want to install it on Kong 1.3.0 ,
(1) i have added it’s name “mirror” to the constants.lua
(2) I put all files of plugins under the folder “plugins/mirror”
(3) i add a item “plugins = bundled,mirror”

when i restart the kong, i got the error

Error: /usr/local/share/lua/5.1/kong/cmd/start.lua:64: nginx: [error] init_by_lua error: /usr/local/share/lua/5.1/kong/init.lua:426: error loading plugin schemas: on plugin ‘mirror’: failed converting legacy schema for mirror: unknown legacy field attribute: “item_schema”
stack traceback:
[C]: in function ‘assert’
/usr/local/share/lua/5.1/kong/init.lua:426: in function ‘init’
init_by_lua:3: in main chunk

how to resolve it , tks for all

We would need to see your schema.lua file but the error is stated here:

Error: /usr/local/share/lua/5.1/kong/cmd/start.lua:64: nginx: [error] init_by_lua error: /usr/local/share/lua/5.1/kong/init.lua:426: error loading plugin schemas: on plugin ‘mirror’: failed converting legacy schema for mirror: unknown legacy field attribute: “item_schema”
stack traceback:
[C]: in function ‘assert’
/usr/local/share/lua/5.1/kong/init.lua:426: in function ‘init’
init_by_lua:3: in main chunk

error loading plugin schemas: on plugin ‘mirror’: failed converting legacy schema for mirror: unknown legacy field attribute: “item_schema”

Reads to me like you are trying to do a legacy schema format but something isn’t looking right, here is an example of a legacy schema file look if your curious: