Add health check

app/src/main/kotlin/controllers/HealthCheckController.kt

@@ -0,0 +1,12 @@
+package be.simplenotes.app.controllers
+
+import be.simplenotes.persistance.DbHealthCheck
+import org.http4k.core.Request
+import org.http4k.core.Response
+import org.http4k.core.Status.Companion.OK
+import org.http4k.core.Status.Companion.SERVICE_UNAVAILABLE
+
+class HealthCheckController(private val dbHealthCheck: DbHealthCheck) {
+    fun healthCheck(request: Request) =
+        if (dbHealthCheck.isOk()) Response(OK) else Response(SERVICE_UNAVAILABLE)
+}

app/src/main/kotlin/modules/CoreModules.kt

@@ -1,9 +1,6 @@
 package be.simplenotes.app.modules
 
-import be.simplenotes.app.controllers.BaseController
-import be.simplenotes.app.controllers.NoteController
-import be.simplenotes.app.controllers.SettingsController
-import be.simplenotes.app.controllers.UserController
+import be.simplenotes.app.controllers.*
 import be.simplenotes.app.views.BaseView
 import be.simplenotes.app.views.NoteView
 import be.simplenotes.app.views.SettingView
@@ -16,6 +13,7 @@ val userModule = module {
 }
 
 val baseModule = module {
+    single { HealthCheckController(get()) }
     single { BaseController(get()) }
     single { BaseView(get()) }
 }

app/src/main/kotlin/modules/ServerModule.kt

@@ -45,6 +45,7 @@ val serverModule = module {
             get(),
             get(),
             get(),
+            get(),
             requiredAuth = get(AuthType.Required.qualifier),
             optionalAuth = get(AuthType.Optional.qualifier),
             apiAuth = get(named("apiAuthFilter")),

app/src/main/kotlin/routes/Router.kt

@@ -2,10 +2,7 @@ package be.simplenotes.app.routes
 
 import be.simplenotes.app.api.ApiNoteController
 import be.simplenotes.app.api.ApiUserController
-import be.simplenotes.app.controllers.BaseController
-import be.simplenotes.app.controllers.NoteController
-import be.simplenotes.app.controllers.SettingsController
-import be.simplenotes.app.controllers.UserController
+import be.simplenotes.app.controllers.*
 import be.simplenotes.app.filters.*
 import be.simplenotes.domain.security.JwtPayload
 import org.http4k.core.*
@@ -22,6 +19,7 @@ class Router(
     private val settingsController: SettingsController,
     private val apiUserController: ApiUserController,
     private val apiNoteController: ApiNoteController,
+    private val healthCheckController: HealthCheckController,
     private val requiredAuth: Filter,
     private val optionalAuth: Filter,
     private val apiAuth: Filter,
@@ -31,7 +29,11 @@ class Router(
 ) {
     operator fun invoke(): RoutingHttpHandler {
 
-        val basicRoutes = ImmutableFilter.then(static(Classpath("/static"), "woff2" to ContentType("font/woff2")))
+        val basicRoutes =
+            routes(
+                "/health" bind GET to healthCheckController::healthCheck,
+                ImmutableFilter.then(static(Classpath("/static"), "woff2" to ContentType("font/woff2")))
+            )
 
         val publicRoutes = routes(
             "/" bind GET public baseController::index,