move and update run-MDTF README.md

Author: wrongkindofdoctor

tools/run-MDTF/doc/README.md

@@ -0,0 +1,17 @@
+# run-MDTF
+Shell driver script to run the MDTF-diagnostics package with the GFDL FRE workflow <br />
+
+Command-line usage:
+
+```
+$ run-mdtf.sh -i /path/to/pp/dir/pp -o out_dir/mdtf -s startyr -e endyr
+```
+
+Input: 
+- A user-specified configuration file `pod_config.json` located in the **config** directory that is run
+   by default. Users should modify this template to run their desired POD(s) and update query parameters such as *realm*
+   A different configuration file can be supplied with the `-l` OPTARG.
+- `-i`: path to the input directory ending in /pp with the target dataset
+- `-o`: path to directory to write the output
+- `-s`: start year of the dataset
+- `-e`: end year of the dataset