GUACAMOLE-317: Add "failover_only" column to database schema for Guacamole connections.

extensions/guacamole-auth-jdbc/modules/guacamole-auth-jdbc-base/src/main/java/org/apache/guacamole/auth/jdbc/connection/ConnectionModel.java

@@ -61,6 +61,13 @@ public class ConnectionModel extends ChildObjectModel {
      */
     private Integer connectionWeight;
 
+    /**
+     * Whether this connection should be reserved for failover. Failover-only
+     * connections within a balancing group are only used when all non-failover
+     * connections are unavailable.
+     */
+    private boolean failoverOnly;
+
     /**
      * The identifiers of all readable sharing profiles associated with this
      * connection.
@@ -196,6 +203,32 @@ public class ConnectionModel extends ChildObjectModel {
         return connectionWeight;
     }
 
+    /**
+     * Returns whether this connection should be reserved for failover.
+     * Failover-only connections within a balancing group are only used when
+     * all non-failover connections are unavailable.
+     *
+     * @return
+     *     true if this connection should be reserved for failover, false
+     *     otherwise.
+     */
+    public boolean isFailoverOnly() {
+        return failoverOnly;
+    }
+
+    /**
+     * Sets whether this connection should be reserved for failover.
+     * Failover-only connections within a balancing group are only used when
+     * all non-failover connections are unavailable.
+     *
+     * @param failoverOnly
+     *     true if this connection should be reserved for failover, false
+     *     otherwise.
+     */
+    public void setFailoverOnly(boolean failoverOnly) {
+        this.failoverOnly = failoverOnly;
+    }
+
     /**
      * Sets the maximum number of connections that can be established to this
      * connection concurrently by any one user.