Adds a node or nodes to an existing cluster.

iex> {c_id, c} = Cluster.new
iex> {n_id, n} = Node.new
iex> {n2_id, n2} = Node.new

# Adding a single node
iex> Cluster.add(c_id, n_id)

# Adding multiple nodes
iex> Cluster.add(c_id, [n_id, n2_id])

Deletes the cluster with the provided cluster_id.

iex> {c_id, c} = Cluster.new
iex> Cluster.delete(c_id)

Find the cluster in the graph that has the provided cluster_id.

Returns the cluster, or nil if it is not found.

iex> {c_id, c} = Cluster.new
iex> Cluster.find(c_id) #=> returns `c`

Create a new cluster.

The cluster is empty by default, but can be provided with nodes already part of it.

iex> {n_id, n} = Node.new
iex> {n2_id, n2} = Node.new

# Passing no node ids
iex> Cluster.new
{3, %{ node_ids: [] }

# Passing a single node id
iex> Cluster.new(n_id)
{3, %{ node_ids: [1] }

# Passing multiple node ids
iex> Cluster.new([n_id, n2_id])
{3, %{ node_ids: [1, 2] }

Removes a node or nodes from an existing cluster.

iex> {n_id, n} = Node.new
iex> {n2_id, n2} = Node.new
iex> {c_id, c} = Cluster.new([n_id, n2_id])

# Removing a single node
iex> Cluster.remove(c_id, n_id)

# Removing multiple nodes
iex> Cluster.remove(c_id, [n_id, n2_id])