Added reviewer section to PR template

.github/PULL_REQUEST_TEMPLATE.md

@@ -1,5 +1,17 @@
+FOR CONTRIBUTOR:
 * [ ] - I have read the [CONTRIBUTING.md](https://github.com/galaxyproject/tools-iuc/blob/master/CONTRIBUTING.md) document
 * [ ] - This tool is appropriate for the tools-iuc repo (see [CONTRIBUTING.md](https://github.com/galaxyproject/tools-iuc/blob/master/CONTRIBUTING.md))
 * [ ] - This PR adds a new tool or tool collection
 * [ ] - This PR updates an existing tool or tool collection
 * [ ] - This PR does something else (explain below)
+
+FOR REVIEWER:
+* [ ] .shed.yml file ok
+* [ ] Indentation is correct
+* [ ] Tool version/build ok
+* [ ] `<command/>`: file names are escaped
+* [ ] Tests
+  - [ ] Parameters are reasonably covered
+  - [ ] Test files are appropriate
+* [ ] Toolshed user `tools-iuc` has access to associated toolshed repo(s)
+* [ ] Complies with other best practice