add_dependency(snapshot_code, file_path, type='ref')
Append a dependency referent to an existing check - in.
All files are uniquely containe by a particular snapshot. Presently,
this method does a reverse lookup by file name. This assumes that
the filename is unique within the system, so it is not recommended
unless it is known that naming conventions will produce unique
file names for every this particular file. If this is not the
case, it is recommended that add_dependency_by_code() is used.
snapshot_code - the unique code identifier of a snapshot
file_path - the path of the dependent file. This function is able
reverse map the file_path to the appropriate snapshot
type - type of dependency. Values include 'ref' and 'input_ref'
ref = hierarchical reference: ie A contains B
input_ref = input reference: ie: A was used to create B
tag - a tagged keyword can be added to a dependency to categorize
the different dependencies that exist in a snapshot
dictionary - the resulting snapshot