set lru cache to 10 hours

services/spelling/app/coffee/ASpell.coffee

@@ -6,8 +6,9 @@ fs = require 'fs'
 settings = require("settings-sharelatex")
 Path = require("path")
 
-cache = LRU(10000)
 OneMinute = 60 * 1000
+opts = {max:10000, maxAge: OneMinute * 60 * 10}
+cache = LRU(opts)
 
 cacheFsPath = Path.resolve(settings.cacheDir, "spell.cache")
 cacheFsPathTmp = cacheFsPath + ".tmp"