Add crash reporting via Crashlytics.

app/src/main/java/cash/z/ecc/android/di/module/AppModule.kt

@@ -57,4 +57,9 @@ class AppModule {
     @Singleton
     @IntoSet
     fun provideFeedbackMixpanel(): FeedbackCoordinator.FeedbackObserver = FeedbackMixpanel()
+
+    @Provides
+    @Singleton
+    @IntoSet
+    fun provideFeedbackCrashlytics(): FeedbackCoordinator.FeedbackObserver = FeedbackCrashlytics()
 }

app/src/main/java/cash/z/ecc/android/feedback/FeedbackCrashlytics.kt

@@ -0,0 +1,26 @@
+package cash.z.ecc.android.feedback
+
+import com.crashlytics.android.Crashlytics
+
+class FeedbackCrashlytics : FeedbackCoordinator.FeedbackObserver {
+    /**
+     * Report non-fatal crashes because fatal ones already get reported by default.
+     */
+    override fun onAction(action: Feedback.Action) {
+        var exception: Throwable? = null
+        exception = when (action) {
+            is Feedback.Crash -> action.exception
+            is Feedback.NonFatal -> action.exception
+            is Report.Error.NonFatal.Reorg -> ReorgException(
+                action.errorHeight,
+                action.rewindHeight,
+                action.toString()
+            )
+            else -> null
+        }
+        exception?.let { Crashlytics.logException(it) }
+    }
+
+    private class ReorgException(errorHeight: Int, rewindHeight: Int, reorgMesssage: String) :
+        Throwable(reorgMesssage)
+}