firebase crash reporting (#67)

* Created app

* Setup firebase for android

* Added crashlytics plugin

* Setup crashlytics for android

* Setup crashlytics for iOS

* Initialized Firebase and crashlytics

* Update README.md

firebase_crash_reporting/android/build.gradle

@@ -0,0 +1,33 @@
+buildscript {
+    ext.kotlin_version = '1.3.50'
+    repositories {
+        google()
+        jcenter()
+    }
+
+    dependencies {
+        classpath 'com.android.tools.build:gradle:3.5.0'
+        classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
+        classpath 'com.google.gms:google-services:4.3.3'
+        classpath 'com.google.firebase:firebase-crashlytics-gradle:2.2.0'
+    }
+}
+
+allprojects {
+    repositories {
+        google()
+        jcenter()
+    }
+}
+
+rootProject.buildDir = '../build'
+subprojects {
+    project.buildDir = "${rootProject.buildDir}/${project.name}"
+}
+subprojects {
+    project.evaluationDependsOn(':app')
+}
+
+task clean(type: Delete) {
+    delete rootProject.buildDir
+}