Create a file named: .gitignore and place this in the same folder as the .git folder

# Exclude the build directory
build/*
 
# Exclude temp nibs and swap files
*~.nib
*.swp
 
# Exclude OS X folder attributes
.DS_Store
 
# Exclude user-specific XCode 3 and 4 files
*.mode1
*.mode1v3
*.mode2v3
*.perspective
*.perspectivev3
*.pbxuser
*.xcworkspace
xcuserdata