The context menu of a ruby file in the Ruby Resource View has a run entry from which the file can be started in run or debug mode.
The Run main menu also offers a menu point for starting a ruby application. Which file is started is determined by the active part (marked with the blue border). This can be the editor or the Ruby Resource View for example. If the Ruby Resource View is active, the file selected in the resource tree is started. If the editor is the active part, the file in the active editor is started.
Every time a file is started from one of the described menu items, a run configuration is created. If the file is started a second time, this run configuration is used again. That allows to add parameters for the start, change the working directory or the interpreter to start with.
The following library paths are always added when the application is started (using the -I option of the ruby interpreter) and are not listed in the configuration dialog:
The directory in which the started file resides
The path of the project in which the started file resides
The path of all dependent projects of the started file's project
