Tagging Species

[philipbjorge]

We'd like to be able to tag species with information such as "Pests of Concern", "Introduced Species", etc.

This could be done as follows:

• Create a new model called SpeciesTag that has a CharField title. This will allow admins to create new Tags.
• Add a Many-To-Many property to the Species model. This will allow admins to add tags to a species (see SimilarSpecies for an example)
• Create a way to view these on the browse page - related to #212