Enable SideLoading for SharePoint Apps
How to enable SideLoading for the SP13 AppStore:
In a "SharePoint 2013 Management Shell...
enable-spfeature "developer" -url "App Store Site Collection URL"
*** you only need to do this to the App Store site collection...
Originally I thought you need to deploy the Developer feature to all site collections, which doesn't seem to be the case after testing it...
But if you do need to deploy a feature to all Site Collections in a Web App, you could use the PS script below... just change the "developer" to the feature name, like "Reporting" or "ShareWithEveryone"
---
Add-PSSnapin Microsoft.SharePoint.PowerShell - erroraction SilentlyContinue
$sites = get-spsite -webapplication "<web application>" -limit all
foreach ($site in $sites) {
enable-spfeature "developer" -url $site.url
write-host "enabled sideloading on" $site.url
}
write-host "Completed"