function onCommand( name, theme ) {
		try {
			repl.addTheme( name, theme );
		} catch ( err ) {
			repl._ostream.write( format( 'Error: %s\n', err.message ) );
			return;
		}
		log( repl, format( '\nSuccessfully added theme `%s`.', name ) );
	}
Adds a syntax highlighting color theme.

@private
@param {string} name - theme name
@param {Object} theme - theme object
@returns {void}