Add .gitignore

.gitignore

@@ -0,0 +1,50 @@
+.DS_Store
+.dart_tool/
+
+.packages
+.pub/
+
+build/
+
+.atom/
+.idea/
+.vscode/
+
+pubspec.lock
+flutter_export_environment.sh
+
+examples/all_plugins/pubspec.yaml
+
+Podfile
+Podfile.lock
+Pods/
+.symlinks/
+**/Flutter/App.framework/
+**/Flutter/ephemeral/
+**/Flutter/Flutter.framework/
+**/Flutter/Generated.xcconfig
+**/Flutter/flutter_assets/
+
+ServiceDefinitions.json
+xcuserdata/
+**/DerivedData/
+
+local.properties
+keystore.properties
+.gradle/
+gradlew
+gradlew.bat
+gradle-wrapper.jar
+.flutter-plugins-dependencies
+*.iml
+
+generated_plugin_registrant.dart
+GeneratedPluginRegistrant.h
+GeneratedPluginRegistrant.m
+GeneratedPluginRegistrant.java
+GeneratedPluginRegistrant.swift
+.flutter-plugins
+
+.project
+.classpath
+.settings