Update README

Author: georgweiss

README.md

@@ -1 +1,72 @@
 This is an attempt to port the original work https://github.com/ornl-epics/pvws to a Spring Boot-based web application. While the code is adapted to the web socket APIs of Spring Boot, most of the code is essentially unchanged.
+
+Requirements
+------------
+
+To build: JDK 17, Maven 3.8+
+
+To run: JRE 17
+
+Build
+=====
+
+Executable jar
+--------------
+
+To build an executable Spring Boot jar (embedded Tomcat):
+
+``>mvn clean install``
+
+Output is ``pvws.jar`` in the ``target`` directory.
+
+Tomcat war
+----------
+
+To build war for deployment in Tomcat container:
+
+``>mvn -Pwar clean install``
+
+Output is ``pvws.war`` in the ``target`` directory.
+
+Run
+===
+
+Settings
+--------
+
+Bundled ``application.properties`` defines a few settings (e.g. default protocol). To define other settings or override
+settings, one may create a file named exactly ``application.properties`` and edit as needed. This
+file must be readable by the user account owning the application process.
+
+Executable jar
+--------------
+
+Launch like so:
+
+``>java -Dspring.config.location=file:/path/to/directory/ -jar /path/to/pvws.jar``
+
+where ``/path/to/directory/`` is the directory holding ``application.properties``. Note that
+this string **must** end in a slash ("/").
+
+It is also possible to define properties on the command line, e.g. 
+
+``>java -Dspring.config.location=file:/path/to/directory/ -DEPICS_PVA_ADDR_LIST=1.2.3.4 -jar /path/to/pvws.jar``
+
+Combining ``application.properties`` with JVM options is possible.
+Command line options will override definitions in ``application.properties``.
+
+Tomcat war
+----------
+
+**NOTE:** Verified on Tomcat 9 only.
+
+Copy ``pvws.war`` to ``TOMCAT_ROOT/webapps``. Set environment variable:
+
+``>export JAVA_OPTS=-Dspring.config.location=file:/path/to/directory/``
+
+and launch Tomcat.
+
+
+
+
+