I added msg.query to the code to use predefined queries. (#19)

msg.topic never used in the code but the readMe says it can hold SQL
queries. I replaced topic with query because topic used several time in
other nodes.

Co-authored-by: Mathias Rangel Wulff <m@rawu.dk>

node-red-contrib-alasql.html

@@ -33,7 +33,7 @@ <h4><a id="Returned_values_25"></a>Returned values</h4>
     </code></pre>
     <p>To manipulate output format please consult the use of <a href="https://github.com/agershun/alasql/wiki/Value"><code>VALUE OF</code></a>, <a href="https://github.com/agershun/alasql/wiki/MATRIX"><code>MATRIX OF</code></a>, <a href="https://github.com/agershun/alasql/wiki/COLUMN"><code>COLUMN OF</code></a>, <a href="https://github.com/agershun/alasql/wiki/ROW"><code>ROW OF</code></a>, and <a href="https://github.com/agershun/alasql/wiki/RECORDSET"><code>RECORDSET OF</code></a>.</p>
     <h4><a id="Multiply_queries_36"></a>Multiply queries</h4>
-    <p>The <code>msg.topic</code> can hold several SQL queries separated by <code>;</code>. The returned value will be an array with the result from each typically returned payload.</p>
+    <p>The <code>msg.query</code> can hold several SQL queries separated by <code>;</code>. The returned value will be an array with the result from each typically returned payload.</p>
     <h4><a id="Binding_parameters_41"></a>Binding parameters</h4>
     <p>The <code>msg.payload</code> will be passed as a binded parameter. You can refer to the value by having <code>$0</code> in your SQL. If <code>msg.payload</code> is an array the first value will be <code>$0</code>, the second <code>$1</code> and so forth.</p>
     <p>Please <a href="https://github.com/agershun/alasql/wiki/readme">consult the AlaSQL wiki</a> to undertand the flexible nature of the library.</p>

node-red-contrib-alasql.js

@@ -6,7 +6,7 @@ module.exports = function (RED) {
         var node = this;
         node.query = config.query;
         node.on("input", function (msg) {
-            var sql = this.query || msg.topic || 'SELECT * FROM ?';
+            var sql = this.query || msg.query || msg.topic || 'SELECT * FROM ?';
             var bind = Array.isArray(msg.payload) ? msg.payload : [msg.payload];
             alasql.promise(sql, bind)
                 .then(function (res) {