add a perceptron classifier to examples

Author: ablaom

docs/src/common_implementation_patterns.md

@@ -22,12 +22,12 @@ implementations fall into one (or more) of the following informally understood p
 
 - [Regression](@ref): Supervised learners for continuous targets
 
-- Classification: Supervised learners for categorical targets 
+- [Classification](@ref): Supervised learners for categorical targets 
 
 - Clusterering: Algorithms that group data into clusters for classification and
   possibly dimension reduction. May be true learners (generalize to new data) or static.
 
-- Gradient Descent: Including neural networks.
+- [Gradient Descent](@ref): Including neural networks.
 
 - [Iterative Algorithms](@ref)
 

docs/src/patterns/classification.md

@@ -1 +1,5 @@
 # Classification
+
+See these examples from tests:
+
+- [perceptron classifier](https://github.com/JuliaAI/LearnAPI.jl/blob/dev/test/integration/gradient_descent.jl)

docs/src/patterns/gradient_descent.md

@@ -0,0 +1,5 @@
+# Gradient Descent
+
+See [this
+example](https://github.com/JuliaAI/LearnAPI.jl/blob/dev/test/integration/gradient_descent.jl)
+from tests.

docs/src/patterns/iterative_algorithms.md

@@ -1,5 +1,7 @@
 # Iterative Algorithms
 
-See [this
-example](https://github.com/JuliaAI/LearnAPI.jl/blob/dev/test/integration/ensembling.jl)
-from tests.
+See these examples from tests:
+
+- [bagged ensembling](https://github.com/JuliaAI/LearnAPI.jl/blob/dev/test/integration/ensembling.jl)
+
+- [perceptron classifier](https://github.com/JuliaAI/LearnAPI.jl/blob/dev/test/integration/gradient_descent.jl)