I am very new to Linux systems; that's why my friends and I are trying to learn linux by developing a meteor app on it. I would also like some advice on my current project. This is what I am thinking currently;

-Each user will have their own sandboxes. (How should I do this?)

-They will pull from Github(Master branch) into their project folders and develop what they are assigned to.

-They will push to Github(to their branches) when they are done.

-When it is ready for testing, we will pull from the users and merge them. Then, we will push it to Github(testing branch).

-We will have a testing sandbox where we pull from Github (testing branch) and test. If everything works, then we will push it to Github(Master branch).

Will the users be able to test their apps when another person is being logged into their accounts? Meteor uses Node.js and I would like to know the ideal RAM for five users that will be running and testing their apps.

Thanks in advance.

If you want each user should be logged into server and should use UI of the server (not only command line) then you should use Device like NComputing vSpace X-Series.
Now you need only individual monitors and one central cpu as server.
You should have 'n' number of NComputing vSpace X-Series devices for 'n' number of users.
Each devices has a VGA port for monitor, two usb ports for keyboard and mouse, an alternate ps/2 port and two Ethernet Ports.
A LAN cable is connected to the CPU and other part of cable is connected to NComputing vSpace X-Series Ethernet port.
Now connect monitor keyboard and mouse to the device and you will see a login screen. Login with your Linux user and you do not need a console login. You can access all installed applications on CPU and you do not need extra CPU.
You can use a Ethernet Port Hub for multiple Ethernet ports and you can connect number of devices to the CPU.
Now you do not need to install applications on every system, just install in Centralized CPU and every connected user will be able to access it.

Check here for details
http://www.ncomputing.com/support/