Tested on OpenWRT

LuCI/controller/cronosagent.lua

@@ -1,12 +1,14 @@
-module("cronosagent", package.seeall)
+module("luci.controller.cronosagent", package.seeall)
 
 function index()
   entry({ "admin", "cronosagent"              }, alias("admin", "cronosagent", "configure", "restart"), "CronosAgent")
-  entry({ "admin", "cronosagent", "configure" }, cbi("cronosagent"),                                    "Configure", 10)
+  entry({ "admin", "cronosagent", "configure" }, cbi("cronosagent/configure"),                          "Configure", 10)
   entry({ "admin", "cronosagent", "restart"   }, call("restartCronosAgent"),                            "Restart",   20)
 end
 
 function restartCronosAgent()
   luci.sys.init.stop("cronosagent")
   luci.sys.init.start("cronosagent")
+  luci.http.write("Done!")
+  -- luci.http.redirect("/")
 end

LuCI/cronosagent

@@ -0,0 +1,5 @@
+config cronosagent
+	option number '123456'
+	option repeaterAddress '1.1.1.1'
+	option serverAddress 'master.dstar.su'
+	option serverPassword 'password'

LuCI/model/cbi/cronosagent/configure.lua

@@ -1,6 +1,6 @@
 
 local map      = Map("cronosagent", "CronosAgent")
-local section  = map:section(TypedSection, "global", "", "Configuration")
+local section  = map:section(TypedSection, "cronosagent", "Configuration")
 
 local number   = section:option(Value, "number",          "Repeater ID",      "DMR ID assigned to your repeater"  )
 local repeater = section:option(Value, "repeaterAddress", "Repeater Address", "Address of your KAIROS repeater"   )
@@ -13,3 +13,5 @@ repeater.datatype = "ip4addr"
 server.datatype   = "host"
 password.datatype = "string"
 password.password = true
+
+return map

LuCI/readme.txt

@@ -0,0 +1,3 @@
+/usr/lib/lua/luci/controller/cronosagent.lua
+/usr/lib/lua/luci/model/cbi/cronosagent/configure.lua
+/etc/config/cronosagent