Add tags feature for projects (and maybe controls?)

[jovinden]

This is something that was partially in the works before Seve left.

Sometimes we have projects that will use samples from multiple studies (like mine) or only a subset of samples from a study. It would be useful to be able to tag all the sample involved in your project. That way I could search for all SeroX samples and pull them up regardless of which study or plate they are on. It may also be handy to be able to see which of your samples overlap with other projects (maybe you can compare data or if the sample is missing you can track it down by finding the owner of that project).

There could be a tags column. Or potentially a project column that can contain multiple values.

Not sure if the projects should be a reference type (like study). May not be necessary but would keep things tight. Metadata for project would likely just be ProjectCode = SeroX, LeadPerson = Joanna Vinden.

It may also be useful to be able to tag a sample as a control sample. I havent thought this part through totally and will discuss more in issue #37 .