Add a work estimate section to the template (#402)

jep-template/0000/README.adoc

@@ -247,6 +247,27 @@ but must be completed before any JEP is given
 JEPs which will not include code changes may omit this section.
 ====
 
+== Work Estimates
+
+[TIP]
+====
+Provide a clear description of the high-level tasks needed to productize the prototype implementation.
+Ideally these tasks would be turned into work items in an issue tracking system (ITS) like Jira or GitHub Issues.
+As a general rule, it should be possible to complete each task within 1-3 days;
+if a task takes a week or longer, it has not been broken down with enough granularity.
+If these tasks are not obvious, then the prototype is not complete enough.
+Also describe the general roles needed to perform these tasks.
+For example, is the task well-suited to a new contributor,
+or does the task require advanced experience in the Jenkins project that demands a seasoned expert?
+Perhaps the task is well-suited to contributors with an affinity for e.g. frontend development, security, or DevOps.
+Finally, describe the nature of the work in relation to time:
+can these tasks be picked up in parallel by any interested volunteers,
+or do they need to be done in some specific order?
+Do any tasks depend on other tasks in a way that would serialize the implementation of the project?
+
+JEPs that do not include a prototype implementation may omit this section.
+====
+
 == References
 
 [TIP]