updated README.md for doctype

Author: shanukus98765

.gitignore

@@ -1,3 +1,4 @@
 robots.txt
 vendor
 composer.lock
+temp/

README.md

@@ -19,3 +19,17 @@ Convert and validate against:
 
 * JS rules for validating the HTML
 * Microdata extraction tests
+
+
+## NOTE:
+For testing against a particular dtd, just add the following below <?xml version="1.0"?> command in your xml file.
+
+```shell
+ <!DOCTYPE article PUBLIC "-//NLM//DTD JATS (Z39.96) Journal Archiving DTD v1.1 20120330//EN"
+    "file://"{{LOCATION}}>
+
+ example of {{Location}}: home/shanu/jats-conversion/schema/jats/archiving/1.1/JATS-Archiving-1-1-MathML3-DTD/JATS-archivearticle1-mathml3.dtd
+
+```
+
+The JATS-Archiving-1-1-MathML3-DTD is the entire folder containing the .dtd modules and .ent modules. You could download the zip file from ftp://ftp.ncbi.nlm.nih.gov/pub/jats/archiving/1.1/