Add .idea to .gitignore

Signed-off-by: Tobias Eidelpes <tobias@eidelpes.info>

.gitignore

@@ -80,25 +80,6 @@ pickle-email-*.html
 # tilde files are usually backup files from a text editor
 *~
 
-# User-specific stuff
-.idea/**/workspace.xml
-.idea/**/tasks.xml
-.idea/**/usage.statistics.xml
-.idea/**/dictionaries
-.idea/**/shelf
-
-# Generated files
-.idea/**/contentModel.xml
-
-# Sensitive or high-churn files
-.idea/**/dataSources/
-.idea/**/dataSources.ids
-.idea/**/dataSources.local.xml
-.idea/**/sqlDataSources.xml
-.idea/**/dynamic.xml
-.idea/**/uiDesigner.xml
-.idea/**/dbnavigator.xml
-
 *.bak
 *.rbc
 .#*
@@ -108,4 +89,5 @@ pickle-email-*.html
 /coverage
 /html
 /pkg
-Gemfile.lock
+Gemfile.lock
+.idea