Add gitignore file

.gitignore

+[Ll]ibrary/
+[Tt]emp/
+[Oo]bj/
+[Bb]uild/
+[Bb]uilds/
+Assets/AssetStoreTools*
+
+# Visual Studio cache directory
+.vs/
+
+# Autogenerated VS/MD/Consulo solution and project files
+ExportedObj/
+.consulo/
+*.csproj
+*.unityproj
+*.sln
+*.suo
+*.tmp
+*.user
+*.userprefs
+*.pidb
+*.booproj
+*.svd
+*.pdb
+*.opendb
+*.VC.db
+
+# Unity3D generated meta files
+*.pidb.meta
+*.pdb.meta
+
+# Unity3D Generated File On Crash Reports
+sysinfo.txt
+
+# Builds
+*.apk
+*.unitypackage
+
+# Crashlytics generated file
+Assets/StreamingAssets/crashlytics-build.properties
+