Environment Variables example (Windows)

The included examples for "Environment Variables" do not work on Windows. This change adds the equivalent commands on Windows using setx.

Author: eshultz

doc/usage_guide.md

@@ -233,10 +233,25 @@ Note this example is for Linux and macOS usage.
 You can set environment variables for your connection string through the following steps:
 
 
+    # (linux/bash)
     # set environment variable MSSQL_SCRIPTER_CONNECTION_STRING with a connection string.
     $ export MSSQL_SCRIPTER_CONNECTION_STRING='Server=myserver;Database=mydb;User Id=myuser;Password=mypassword;'
     $ mssql-scripter
 
+    # (linux/bash)
     # set environment variable MSSQL_SCRIPTER_PASSWORD so no password input is required.
     $ export MSSQL_SCRIPTER_PASSWORD='[PLACEHOLDER]'
     $ mssql-scripter -S localhost -d AdventureWorks -U sa
+
+    # (windows)
+    # set environment variable MSSQL_SCRIPTER_CONNECTION_STRING with a connection string.
+    setx MSSQL_SCRIPTER_CONNECTION_STRING 'Server=myserver;Database=mydb;User Id=myuser;Password=mypassword;'
+    # note: you must start a new PS session for the change to take effect
+    mssql-scripter
+    
+    # (windows)
+    # set environment variable MSSQL_SCRIPTER_PASSWORD so no password input is required.
+    setx MSSQL_SCRIPTER_PASSWORD mypassword
+    # note: you must start a new PS session for the change to take effect
+    $ mssql-scripter -S localhost -d AdventureWorks -U sa
+