updated readme with ```shell

README.md

@@ -127,14 +127,14 @@ See below section for examples on how to use volume and port mapping.
 Edit the .env file with the following entries.
 
 Required:
-```
+```shell
 INFORMATICA_USER=xxxx
 INFORMATICA_PASSWORD=xxxx
 HOSTNAME=xxxx
 ```
 
 Optional (for volumes):
-```
+```shell
 CONFIG_DIR=
 LOG_DIR=
 ODBC_DATABASE_DIR=
@@ -148,9 +148,10 @@ The included docker-compose.yml file uses the above environment variables to map
 For volumes, add volume folders in directory.
 For no volumes, delete lines 15 - 32 on docker-compose.yml
 
+```shell
 $ docker-compose build
 $ docker-compose up
-
+```
 
 #### Starting with docker run