add a new function for `(now-with-format)` which accepts a single argument...

add a new function for `(now-with-format)` which accepts a single argument which is a date format as a string and formats the current time to the given format.  this makes it easy to get the current time in any format the caller wants.

src/metabase/util.clj

@@ -108,6 +108,11 @@
   []
   (time/unparse (time/formatters :date-time) (coerce/from-long (System/currentTimeMillis))))
 
+(defn now-with-format
+  "format the current time using a custom format."
+  [format]
+  (time/unparse (time/formatter format) (coerce/from-long (System/currentTimeMillis))))
+
 (defn jdbc-clob->str
   "Convert a `JdbcClob` to a `String`."
   (^String