Revise .gitignore.

Author: gregturn

.gitignore

@@ -1,13 +1,46 @@
-
-# Created by https://www.gitignore.io/api/maven,intellij
-# Edit at https://www.gitignore.io/?templates=maven,intellij
+# Created by https://www.gitignore.io/api/intellij,maven
+# Edit at https://www.gitignore.io/?templates=intellij,maven
 
 ### Intellij ###
 # Covers JetBrains IDEs: IntelliJ, RubyMine, PhpStorm, AppCode, PyCharm, CLion, Android Studio and WebStorm
 # Reference: https://intellij-support.jetbrains.com/hc/en-us/articles/206544839
 
 # User-specific stuff
-.idea/
+.idea
+
+# Gradle and Maven with auto-import
+# When using Gradle or Maven with auto-import, you should exclude module files,
+# since they will be recreated, and may cause churn.  Uncomment if using
+# auto-import.
+# .idea/modules.xml
+# .idea/*.iml
+# .idea/modules
+*.iml
+# *.ipr
+
+# CMake
+cmake-build-*/
+
+# Mongo Explorer plugin
+.idea/**/mongoSettings.xml
+
+# File-based project format
+*.iws
+
+# IntelliJ
+out/
+
+# mpeltonen/sbt-idea plugin
+.idea_modules/
+
+# JIRA plugin
+atlassian-ide-plugin.xml
+
+# Crashlytics plugin (for Android Studio and IntelliJ)
+com_crashlytics_export_strings.xml
+crashlytics.properties
+crashlytics-build.properties
+fabric.properties
 
 ### Maven ###
 target/
@@ -20,5 +53,6 @@ dependency-reduced-pom.xml
 buildNumber.properties
 .mvn/timing.properties
 .mvn/wrapper/maven-wrapper.jar
+.flattened-pom.xml
 
-# End of https://www.gitignore.io/api/maven,intellij
+# End of https://www.gitignore.io/api/intellij,maven