add github ci (tests gradle build)

Author: edwardwawrzynek

.github/workflows/main.yml

@@ -0,0 +1,20 @@
+name: Gradle Build
+
+on:
+  push:
+    branches: [ $default-branch ]
+  pull_request:
+    branches: [ $default-branch ]
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v2
+    - name: Set up JDK 11
+      uses: actions/setup-java@v2
+      with:
+        java-version: '11'
+        distribution: 'adopt'
+    - name: Gradle Build
+      run: ./gradlew build

src/main/kotlin/frc/robot/subsystems/DrivetrainSubsystem.kt

@@ -12,6 +12,8 @@ import edu.wpi.first.wpilibj2.command.SubsystemBase
 import edu.wpi.first.wpilibj.smartdashboard.SmartDashboard
 import frc.robot.Constants
 import kotlin.math.IEEErem
+import kotlin.math.abs
+import kotlin.math.min
 
 /**
  * Drivetrain subsystem