./gradlew :buildPlugin
Add ./build/distributions/idea-native2-debugger-1.0-SNAPSHOT.zip to IntelliJ IDEA plugins. To to that, in IntelliJ IDEA, press Ctrl-Alt-S, then go to Plugins, then click the gear icon and then go to Install Plugin from Disk....
In order to run your program under the debugger for the first time, go to Run, Edit configurations..., then add a configuration using the + icon, and choose Native2Debugger.
From then on, choose this configuration using the bug icon in order to make the plugin run your program under gdb.
Note that this currently does NOT build your project first--so make sure to build it when you want to.
There are further settings available in Ctrl-Alt-S, Build, Execution, Deployment, Native2 Debugger. There are settings you can use to connect to a remote machine that you want to debug, and there is a setting to specify which gdb to use.