expand readme (#18)

* expand readme

* Update CI.yml

.github/workflows/CI.yml

@@ -22,24 +22,16 @@ jobs:
         arch:
           - x64
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v4
       - uses: julia-actions/setup-julia@v1
         with:
           version: ${{ matrix.version }}
           arch: ${{ matrix.arch }}
-      - uses: actions/cache@v1
-        env:
-          cache-name: cache-artifacts
-        with:
-          path: ~/.julia/artifacts
-          key: ${{ runner.os }}-test-${{ env.cache-name }}-${{ hashFiles('**/Project.toml') }}
-          restore-keys: |
-            ${{ runner.os }}-test-${{ env.cache-name }}-
-            ${{ runner.os }}-test-
-            ${{ runner.os }}-
+      - uses: julia-actions/cache@v1
       - uses: julia-actions/julia-buildpkg@v1
       - uses: julia-actions/julia-runtest@v1
       - uses: julia-actions/julia-processcoverage@v1
-      - uses: codecov/codecov-action@v1
+      - uses: codecov/codecov-action@v4
         with:
           file: lcov.info
+          token: ${{ secrets.CODECOV_TOKEN }} # required

README.md

@@ -1,2 +1,22 @@
 # RFFT.jl
+
 In-place real FFTs for Julia
+
+For example
+```julia
+import RFFT
+
+a = rand(Float64, 100, 150)
+
+# initialize a buffer 'RCpair' that contains a real and complex space
+buf = RFFT.RCpair{Float64}(undef, size(a))
+
+# create the plan
+plan = RFFT.plan_rfft!(buf; flags=FFTW.MEASURE)
+
+# use the plan and buffer on a new array
+new = rand(Float64, 100, 150)
+copy!(buf, new)
+new_fft = plan(buf)
+
+```